RELATIVE CLAUSES
Defining relative clauses
We
use defining relative clauses to give essential information about someone or
something – information that we need in order to understand what or who is
being referred to. A defining relative clause usually comes immediately after
the noun it describes.
We
usually use a relative pronoun (e.g. who, that, which, whose andwhom) to introduce a
defining relative clause (In the examples, the relative clause is in bold, and the person
or thing being referred to is underlined.):
They’re the
people who want to buy our
house.
Here are some
cells which have been
affected.
They should give the money to
somebody who they think
needs the treatment most.
Non-defining relative clauses
We use non-defining
relative clauses to give extra information about the person or thing. It is not
necessary information. We don’t need it to understand who or what is being
referred to.
We always use a relative pronoun (who, which, whose or whom) to introduce a
non-defining relative clause (In the examples, the relative clause is in bold, and the person
or thing being referred to is underlined.)
Clare, who I work with, is doing the
London marathon this year.
Not: Clare, I work with, is doing the London marathon this year.
Doctors use the testing kit for regular screening for lung and stomach cancers, which account for 70% of cancers
treated in the western world.
CONDITIONAL SENTENCES
The most common kind of conditional sentence that you are
likely to meet will contain two clauses, one of which will start with the word
if, as in If it rains, we'll have to stay at home. The clause without the if is
the main clause of the sentence, while the if clause is subordinate. The order
of the two clauses is generally not that important to the meaning of the
sentence; so we can switch the if clause to the end of the sentence if we want
to.
Most grammar books tend to recognise four basic
configurations of tenses in conditional sentences which vary in structure
according to the time that we are talking about (past, present or future) and
the meaning. These four types are normally referred to as the zero, first,
second and third conditionals; we will look at the forms and meanings of each
of these in turn and also examine some of the alternatives to these four basic
types.
1. Conditional Sentence Type 0 conditional
Conditional type zero is used to talk about general truths,
scientific facts or things which always happen under certain conditions.
|
If + Simple Present, + Simple Present
|
Examples:
- - If you cross an international date line, the
time changes.
- - Phosphorus burns if you expose it to air.
- - If I wake up early, I go jogging.
2. Conditional Sentence Type 1
Often called the "real" conditional because it is
used for real or possible situations. These situations take place if a certain
condition is met. It is possible and also very likely that the condition will
be fulfilled.
|
If + Simple Present, +
Simple Future
|
Example:
- - If I have enough time, I'll watch the football
match.
- - I may have time to watch the match but I'm not
sure about it.
3. Conditional Sentence Type 2
Often called the "unreal" conditional because it
is used for unreal impossible or improbable situations. This conditional
provides an imaginary result for a given situation. It is very unlikely that
the condition will be fulfilled.
|
if +
Simple Past, + would + base verb
|
Example:
- - If I were a millionaire, I would buy a castle.
4. Conditional Sentence Type 3
It is impossible that the condition will be met because it
refers to the past.
|
if +
Past Perfect, + would + have + Past Participle
|
Example:
- - If he had been careful, he wouldn't have had
that terrible accident.
- - Sometimes in the past, he was careless. He drove
so fast. So he had a terrible accident
