Grammar Plus B2

UNIT

19

Modals (3): deduction; compound forms MODAL VERBS EXPRESSING DEDUCTION Modal verbs can be used to expressed different degrees of certainty. Here is a list starting from the maximum level and ending with the least level of certainty.

MUST

almost certain (90%)

That must be Cheryl’s car. (I’m quite sure it is)

SHOULD

very likely (60%)

That should be Cheryl’s car. (I think it is)

COULD

possible (50%)

That could / may be Cheryl’s car. (I can’t tell)

MIGHT

uncertain (40%)

That might be Cheryl’s car. (I have no idea)

MUST

very uncertain (20%)

That may not be Cheryl’s car. (I have no idea)

MAY / MIGHT NOT

impossible (10%)

That can’t be Cheryl’s car. (I’m sure it isn’t)

The same can be done with modal verbs in the Past form. The compound form of modal verbs is based on this typical structure: MODAL + HAVE + PAST PARTICIPLE (PP) MUST HAVE + PP

almost certain

The film must have been boring.

COULD HAVE + PP

possible

She could have left her phone at home.

MAY (not) HAVE + PP MIGHT (not) HAVE + PP CAN’T HAVE + PP

uncertain impossible

He may have known the killer.

They mightn’t have recognised us.

I can’t have signed this document.

OTHER COMPOUND MODALS SHOULD (not) HAVE + PP OUGHT TO HAVE + PP COULD HAVE + PP

Expressing regret about something that didn't happen in the past.

We shouldn’t have wasted so much money on that.

She ought to have taken that chance.

I could have studied harder.

DON’T / DIDN’T NEED TO or NEEDN’T HAVE + PP In the Past tense there is a little difference between these two forms. Compare the examples: Ann told us we didn’t need to bring any drinks (we knew it wasn’t necessary to do it).

We needn’t have brought the umbrellas: it was sunny all day (but we didn’t know that when we left).

OTHER FORMS EXPRESSING DUTY, OBLIGATION AND NECESSITY • Be expected to is used when something is very likely to happen, we expect it to happen: The storm is expected to move southward during the night.

• Be obliged / compelled / forced to are used when an action is caused by something: Because of the flood we were forced to close down.

• Be bound to is used when something is destined to happen or will happen for sure: It was bound to happen sooner or later. We should have known better.

• Be due to it is used for things that are planned or expected to happen at a certain time or moment: Our train is due to arrive at Glasgow Central at 12:12.

• Be to is used as a short form for ‘be going to’ (especially in the news) or to give formal / impersonal instructions and orders about actions that must or mustn’t be carried out: The Pope is to visit the Philippines (or: ...is going to visit ...) .

The test papers are to be handed in by 9.30AM. (or: ...must be handed in...)

Guests are to leave the premises in a clean and tidy condition. (or must leave...)

• Be meant to is similar to be bound to and is used when something is destined to happen Laura was meant to be a mother: she’s so patient and loving.

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