modals of posibility in the past

Look! Our car isn't in the driveway! Somebody .... have stolen it

• must

• can

• might

• could

Answer explanation

The correct choice is 'must' because the absence of the car in the driveway strongly indicates that it has been stolen. 'Must' conveys a high level of certainty about this conclusion.

My plants are dead. I ... (give) them enough water.

Answer explanation

The correct choice is "can't have given" because it indicates a past action that was impossible. The speaker believes they provided enough water, but the dead plants suggest otherwise, making it impossible they did.

I don't know why he hasn't called me back. He .... (forget) my number

Answer explanation

The correct choice is 'might have forgotten' because it suggests a possibility regarding his action of forgetting the number, which fits the context of uncertainty in the statement.

It's Monday, 10:00 a.m. He   .....   (be) in the office now.

Answer explanation

The correct choice is 'must be' because it indicates a strong assumption about his presence in the office at 10:00 a.m. on Monday, suggesting that it is very likely he is there.

They live in a very big and luxusious house. They  ....     rich

• can be

• must be

• could be

• could have been

• can't have been

Answer explanation

The phrase 'They live in a very big and luxurious house' implies a high standard of living, suggesting they 'must be' rich. This choice indicates a strong conclusion based on the evidence provided.

I can't find my car keys. They are not at home, so I     (leave)  them in my office

Answer explanation

The phrase 'I can't find my car keys' implies they are not in the current location. Since they are not at home, the logical conclusion is that I must have left them in my office.

There is no one by the name Lisa here. You ....     

• must misdialed

• must have misdialed

• could misdialed

• might have misdialed

Answer explanation

The correct choice is 'must have misdialed' because it indicates a strong conclusion based on the evidence that no one named Lisa is present. The other options are less definitive and do not convey the same level of certainty.

Don't ring the doorbell when you get there. Maria's little baby  .....  (be)   sleeping

Answer explanation

The correct choice is 'can be' because it indicates a possibility in the present tense. The sentence suggests that the baby is currently sleeping, making 'can be' the appropriate form to express this situation.

That woman _____________ be a doctor! She looks far too young

• can

• can't

• mustn't

• might not

Answer explanation

The correct choice is "can't" because the speaker is expressing disbelief that the woman could be a doctor due to her young appearance. "Can't" indicates impossibility, fitting the context of the statement.

Julie _____________ have much money, or she would buy a new car. Her old one is falling apart.

• must

• mustn't

• can't

• can

Answer explanation

The correct choice is "can't" because it indicates that Julie does not have money, which explains why she isn't buying a new car. "Must" and "mustn't" imply obligation or prohibition, which doesn't fit the context.