3 Question types

There are two main types of questions. Those which require a Yes / No answer, and information or Wh-questions, which ask for specific information.

Yes I No questions

These begin with an auxiliary verb, such as do, am / is / are, have / has, can, could, will, must, etc.

Positive Short answers

Have you finished the Yes, I have,

prototype?

Does the prototype work? Yes, it does.

Will the designs be ready in Yes, they will,

time?

= auxiliary verb + subject + main verb (+ object) Negative

Haven't you finished the No, I haven't,

prototype?

Doesn't the prototype work? No, it doesn't.

Won't the designs be ready No, they won't.

in time?

= auxiliary verb + not + subject + main verb (+ object)

Information questions

These begin with question words, such as what who, when, where, why, which, and how. We can use how in other combinations, such as how much, how many, how long, how far, how safe, etc.

The question words what, which, how much, and how many can be followed by a noun.

Grammar reference 117

What do you think of this solution?

How many machines has the company bought?

= question word (+ object) + auxiliary + subject + main verb

In the two sentences above, the question word is the object of the main verb. Note that what, who, which, how much, how many can also be the subject of a question. In this case, the word order is the same as in a positive sentence.

Which solution works best?

How many machines are in here? Who designed the prototype?

= question word (+ subject) + main verb

4 Used to, used for у made of, made from

We use used to and used for to describe how materials are used. We use made of and made from to talk about the materials that a product consists of.

used to

Rubber is used to make the pedals. = subject + is / are used to + infinitive

used for

Leather is used for making footballs. = is / are used for + -ing form

We can use used to and used for in a similar way. Nylon is used to make / used for making a lot of different products.

Note: Don't confuse these expressions with be used to + -ing form, which means 'be accustomed to'.

made of

Some bottles are made of plastic. = subject + is / are made of + noun made from

Steel is made from iron and carbon. = subject + is / are made from + noun Made from emphasizes the result of a process, while

made ofsimply lists the materials that a product consists of. However, in practice, these expressions are often used to have the same meaning.

Some bottles are made of/ made from plastic. Steel is made of / made from iron and carbon.

5 Time clauses

We use when, as, before, after to show clearly the order in which different events happened. The part of the sentence that begins with the time expression is called the 'time clause'.

when

We use when to refer to actions that happen at almost the same time. One action is an immediate consequence of another. Note that when the time clause comes first, it must be followed by a comma. When you turn the handle, the wheel starts to move.

We can change the two parts of the sentence around, but when must always come before the first action in the sequence of events. The wheel starts to move when you turn the handle.

When the time clause comes later in the sentence, we do not use a comma to separate the two clauses.

as

We use as to talk about two actions that happen at the

same time. The position of the time clause can change,

in the same way as for when.

As the wheel turns, it generates electricity.

The wheel generates electricity as it turns.

Note that in the second as sentence, we need to use a subject the wheel, because by changing the order of the clauses, it is no longer clear what it refers to.

before and after

Before and after also indicate the sequence of events, but there is not necessarily such a close time relationship as with when and as. Before and after simply indicate that one action happened at an unspecified time before another.

Again, the position of the time clause can change.

Before you operate the machine, you must read the

manual.

You must read the manual before you operate the

machine.

118 Grammar reference

Trevor Baylis developed his clockwork radio after he visited Africa.

After he visited Africa, Trevor Baylis developed his clockwork radio.

Before and after can be followed by the -ing form instead of subject + verb.

Before operating the machine,you must read the

manual.

After visiting Africa, Trevor Baylis developed his

clockwork radio.