Time clauses
The time clauses in the English language are introduced by conjunctions such as after, as soon as, before, till, until, when, whenever, while or expressions such as the minute, the moment etc. We do not use the future tense (will) in a time clause to describe future activities.
Compare:
I'll come back home and I'll do it. (x)
I'll do it when I come back home. (when I come is the time clause)
You will push this button and the door will open. (x)
As soon as you push this button the door will open.
Don't stand up. First I'll tell you. (x)
Don't stand up till (until) I tell you.
You'll need my car. Take it. (x)
Whenever you need my car you can take it.
You'll tidy up the house and I'll do the shopping. (x)
You'll tidy up the house while I do the shopping.
You will drop the bomb and it will explode. (x)
The moment you drop the bomb it will explode.
Similarly, other future forms also change to the present simple tense in time clauses.
He is going to leave. The room will be empty. (x)
As soon as he leaves the room will be empty.
We are moving next week. Then we'll call you. (x)
When we move next week we'll call you.
If we describe an action that is happening at the same time as another future action (the two activities are simultaneous), we use the present continuous tense in the time clauses.
We are going to cut the grass. You'll pick the apples. (x)
While we are cutting the grass you'll pick the apples.
The future perfect tense and future perfect continuous become the present perfect and present perfect continuous in time clauses.
I'll have finished my homework in ten minutes. Then I'll go out. (x)
After I have finished my homework I'll go out.
They will have repaired our car by the weekend. And we will go for a trip. (x)
As soon as they have repaired our car we will go for a trip.
Be careful!
If when introduces a noun clause which is the object of a verb, it is followed by a future tense.
I don't know when she will arrive.
I can't remember when the race will start.
You must decide when you will meet them.
In all these sentences the question is: What? (I don't know what, I can't remember what, You must decide what.). That is why it is not a time clause.
The time clauses in the English language are introduced by conjunctions such as after, as soon as, before, till, until, when, whenever, while or expressions such as the minute, the moment etc. We do not use the future tense (will) in a time clause to describe future activities.
Compare:
I'll come back home and I'll do it. (x)
I'll do it when I come back home. (when I come is the time clause)
You will push this button and the door will open. (x)
As soon as you push this button the door will open.
Don't stand up. First I'll tell you. (x)
Don't stand up till (until) I tell you.
You'll need my car. Take it. (x)
Whenever you need my car you can take it.
You'll tidy up the house and I'll do the shopping. (x)
You'll tidy up the house while I do the shopping.
You will drop the bomb and it will explode. (x)
The moment you drop the bomb it will explode.
Similarly, other future forms also change to the present simple tense in time clauses.
He is going to leave. The room will be empty. (x)
As soon as he leaves the room will be empty.
We are moving next week. Then we'll call you. (x)
When we move next week we'll call you.
If we describe an action that is happening at the same time as another future action (the two activities are simultaneous), we use the present continuous tense in the time clauses.
We are going to cut the grass. You'll pick the apples. (x)
While we are cutting the grass you'll pick the apples.
The future perfect tense and future perfect continuous become the present perfect and present perfect continuous in time clauses.
I'll have finished my homework in ten minutes. Then I'll go out. (x)
After I have finished my homework I'll go out.
They will have repaired our car by the weekend. And we will go for a trip. (x)
As soon as they have repaired our car we will go for a trip.
Be careful!
If when introduces a noun clause which is the object of a verb, it is followed by a future tense.
I don't know when she will arrive.
I can't remember when the race will start.
You must decide when you will meet them.
In all these sentences the question is: What? (I don't know what, I can't remember what, You must decide what.). That is why it is not a time clause.
Relative clauses
Defining relative clauses : They specify a noun or pronoun in the main clause and are necessary if we want to understand the meaning of a sentence.
I saw the girl who was outside our house.
They wanted the picture that cost two pounds.
These relative clauses specify the objects of the main clauses. If we omit them, it is not clear what girl or picture we are talking about. The defining relative clauses follow after the relative pronouns who, which, that, whose and whom . We do not write them with commas.
Use of the relative pronouns
Who for persons = The man who called you has just arrived.
Which for things = This is the book which I wanted.
That for persons and things = Are you the boy that lives next door? Can you see the tree that has no leaves?
The relative pronoun that is less formal than who or which.
Whose is a possessive pronoun for persons and things
It is a story about a boy whose parents got divorced.
The river whose bridge is in front of us is called the Cam.
Whom is the object of a verb
The man whom I met yesterday ...
Whom is very formal. In spoken English who or that are much more common.
The man who I met ... The man that I met ...
We can also leave out the pronoun.
It is the most usual form. The man I met ...
If the subject in the main clause is different from the subject in the defining relative clause, we normally leave out the relative pronoun.
The student you saw in Oxford is my neighbor . (the subjects are the student and you )
The bike she borrowed belongs to me . (the subjects are the bike and she )
Be careful = If the subject in the main clause and the relative clause is the same, we cannot omit the pronoun, because it becomes the subject of the relative clause.
The driver who took you to school is from York.
The pen that is on the desk is new.
There is only one subject in each sentence - the driver and the pen . If we leave out the subject, it will not be clear what we mean. The driver took you to school is from York. ( This sentence does not make any sense.)
Relative pronouns with prepositions = We use the relative pronouns with prepositions as follows.
The man I got it from .....
The man who/that I got it from .....
The man from whom I got it .....
The last sentence is not very common in spoken English as it is quite formal.
Non-defining relative clauses : They only describe a preceding noun or pronoun (add some information about them), but do not specify them. The non-defining relative clauses must be written with commas.
My father, who is 65 now, still works.
His car, which cost nearly 20,000 pounds, is broken.
If we leave out these relative clauses (My father still works. His car is broken.) , the sentences remain grammatically correct and we know what father or car we are talking about. The only effect is that there is less information in the sentences.
More examples
I gave it to Peter, who is my close friend.
Ann, whom I admire, is not right in this case.
Their garden, which is near here, looks beautiful.
Pam, whose children go to school, is not so busy.
The non-defining relative clauses are quite formal and are typical of written English. In spoken English we prefer less formal structures. Written English:
Spoken English : My father, who is 65 now, still works.
Written English : My father is 65 now and still works.
Spoken English : Their garden, which is near here, looks beautiful.
Written English : Their garden is near here. It looks beautiful.
In informal English we use who instead of whom .
Formal: Sam, whom I know quite well, would be a good husband.
Informal: Sam, who I know quite well, would be a good husband.
Connective relative clauses : Connective clauses do not define or describe the preceding nouns or pronouns, but only develop the story.
I gave the letter to James, who sent it to London.
She passed me the salt, which fell on the floor.
The function of the connective clauses is different, but the rules are the same as with the non-defining clauses. We make them with the pronouns who, whom, whose, which and write them with commas.
Remember : We cannot write the defining relative clauses with commas, because they change the meaning of a sentence. Compare the following sentences.
The passengers who fastened their seatbelts survived. (Which passengers survived? Only the passengers wearing the seatbelts.)
The passengers, who fastened their seatbelts, survived. (Because all the passengers were wearing their seatbelts, they survived.)
In spoken English we make pauses in sentences instead of commas.
Defining relative clauses : They specify a noun or pronoun in the main clause and are necessary if we want to understand the meaning of a sentence.
I saw the girl who was outside our house.
They wanted the picture that cost two pounds.
These relative clauses specify the objects of the main clauses. If we omit them, it is not clear what girl or picture we are talking about. The defining relative clauses follow after the relative pronouns who, which, that, whose and whom . We do not write them with commas.
Use of the relative pronouns
Who for persons = The man who called you has just arrived.
Which for things = This is the book which I wanted.
That for persons and things = Are you the boy that lives next door? Can you see the tree that has no leaves?
The relative pronoun that is less formal than who or which.
Whose is a possessive pronoun for persons and things
It is a story about a boy whose parents got divorced.
The river whose bridge is in front of us is called the Cam.
Whom is the object of a verb
The man whom I met yesterday ...
Whom is very formal. In spoken English who or that are much more common.
The man who I met ... The man that I met ...
We can also leave out the pronoun.
It is the most usual form. The man I met ...
If the subject in the main clause is different from the subject in the defining relative clause, we normally leave out the relative pronoun.
The student you saw in Oxford is my neighbor . (the subjects are the student and you )
The bike she borrowed belongs to me . (the subjects are the bike and she )
Be careful = If the subject in the main clause and the relative clause is the same, we cannot omit the pronoun, because it becomes the subject of the relative clause.
The driver who took you to school is from York.
The pen that is on the desk is new.
There is only one subject in each sentence - the driver and the pen . If we leave out the subject, it will not be clear what we mean. The driver took you to school is from York. ( This sentence does not make any sense.)
Relative pronouns with prepositions = We use the relative pronouns with prepositions as follows.
The man I got it from .....
The man who/that I got it from .....
The man from whom I got it .....
The last sentence is not very common in spoken English as it is quite formal.
Non-defining relative clauses : They only describe a preceding noun or pronoun (add some information about them), but do not specify them. The non-defining relative clauses must be written with commas.
My father, who is 65 now, still works.
His car, which cost nearly 20,000 pounds, is broken.
If we leave out these relative clauses (My father still works. His car is broken.) , the sentences remain grammatically correct and we know what father or car we are talking about. The only effect is that there is less information in the sentences.
More examples
I gave it to Peter, who is my close friend.
Ann, whom I admire, is not right in this case.
Their garden, which is near here, looks beautiful.
Pam, whose children go to school, is not so busy.
The non-defining relative clauses are quite formal and are typical of written English. In spoken English we prefer less formal structures. Written English:
Spoken English : My father, who is 65 now, still works.
Written English : My father is 65 now and still works.
Spoken English : Their garden, which is near here, looks beautiful.
Written English : Their garden is near here. It looks beautiful.
In informal English we use who instead of whom .
Formal: Sam, whom I know quite well, would be a good husband.
Informal: Sam, who I know quite well, would be a good husband.
Connective relative clauses : Connective clauses do not define or describe the preceding nouns or pronouns, but only develop the story.
I gave the letter to James, who sent it to London.
She passed me the salt, which fell on the floor.
The function of the connective clauses is different, but the rules are the same as with the non-defining clauses. We make them with the pronouns who, whom, whose, which and write them with commas.
Remember : We cannot write the defining relative clauses with commas, because they change the meaning of a sentence. Compare the following sentences.
The passengers who fastened their seatbelts survived. (Which passengers survived? Only the passengers wearing the seatbelts.)
The passengers, who fastened their seatbelts, survived. (Because all the passengers were wearing their seatbelts, they survived.)
In spoken English we make pauses in sentences instead of commas.