Could

We often usecouldto make suggestions:

A:

Will’s party is fancy-dress.

B:

It’s Halloween.

C:

Oh right. Icouldgo as Julius Caesar.

B:

Again? How many times have you done that?

A:

I’ve got to be in the meeting at 10 and the train doesn’t get in until 10.15.

B:

Couldyou get an earlier train?

We usecouldto ask for permission.Couldis more formal and polite thancan:

CouldI ask you a personal question?

When actual past achievements arementioned, we usually usewas/were able toormanaged tobut notcouldin affirmative clauses. This is because they are facts, rather than possibilities:

Iwas able to/managed tobuy a wonderful bag to match my shoes.

Not:I could buy a wonderful bag to match my shoes.

We hired a car and wewere able to/managed todrive 1,000 miles in one week.

Not:We hired a car and we could drive 1,000 miles in one week.

We usecouldto talk about past ability:

When I was young, Icouldeasily touch my toes.

We usecould have + -edform to talk about possibility in the past:

Icould have beena lawyer.

Theycould have takena taxi home instead of walking and getting wet.

Janettecouldn’t have doneany better.

When we want to guess or predict something, we usecouldn’tas the negative form ofmust. We usecouldn’t have +-edform as the negative form ofmust have +-ed. Couldn’tandcouldn’t have +-edform express strong possibility:

She must have made a mistake. Itcouldn’t be true.

A fireworkcouldn’t have doneall that damage.

We usecouldto refer to single events that happened in the past, with verbs of the senses (smell,taste,see,hear,touch, etc.) and mental processes (think,believe,remember,understandetc.):

The food was terrible. Icould tastenothing but salt.

We knew they were in there. Wecould hearvoices inside.

He came and spoke to me, but Icouldn’t rememberhis name.

We usecouldwhen reporting clauses withcanas past events:

They told us wecouldwait in the hallway.(The original words were probably: ‘You can wait in the hallway.’)

She said wecouldbook the tickets online.(The speaker remembers hearing ‘You can book the tickets online.’)

We often usecould have+ -edform to express disapproval or criticism:

Youcould havecalled to say you would be late.(You didn’t call – I think you should have called.)

Youcould havetidied your room.

We usecould have+ -edform to talk about things that did not happen and sometimes to expresses regret:

Hecould have beena doctor.

Icould have beenfamous.

We often use the expressionhow could you/she/he/they?to show disapproval (to show that we don’t like what someone has done):

Grandfather,how could you?How could youleave me?

How could youhave gone without telling me?

A:

We had to give away our dog when we moved to England.

B:

Oh,how could you?