Modals: Speculation, deduction, probabity (past and present)

They ___ be somewhere here, but I can't find it right now.

• can't

• must

Dave ____ (NOT LEAVE) yet - his coat is still here.

The traffic's really bad - I'm worried we ___ (MISS) our train.

You ___ remember me - we met on a trip to China last year.

• can't

• may

What? You forgot your ticket and passport? You ___ be serious!

• might

• can't

You failed the exam, so your answers ___ have been wrong.

• must

• can't

• can

I'm not sure if you're right. You ___ have made a mistake.

• could

• can't

I might ___ (LEAVE) my mobile phone at the hotel, but I don't remember.

Susan has been travelling for the last two weeks - she must ___ (BE) very tired by now.

Wendy's accent is a bit srange. She could ___ (BE) Northern Irish, but I'm not sure.