Cambridge B1 Preliminary (PET) — All Questions

I ___ my keys, so I can't get into the flat.

• a.lose
• b.was losing
• c.have lost✓
• d.losing

The present perfect 'have lost' links a past action to a present result (you can't get in now). The past simple would need a finished time expression.

If it ___ tomorrow, we'll go to the beach.

• a.is sunny✓
• b.will be sunny
• c.would be sunny
• d.was sunny

In the first conditional the 'if' clause uses the present simple, and the main clause uses 'will'. So 'If it is sunny, we'll go...' is correct.

This exercise is ___ than the last one.

• a.difficult
• b.more difficult✓
• c.most difficult
• d.difficulter

'Difficult' is a long adjective, so the comparative uses 'more difficult', followed by 'than'. Long adjectives do not add -er.

You look tired. You ___ go to bed early tonight.

• a.must to
• b.can
• c.would
• d.should✓

'Should' gives advice, which fits a suggestion for someone who looks tired. 'Must to' is never correct (no 'to' after 'must').

She asked me where I ___ from.

• a.come
• b.came✓
• c.have come
• d.coming

In reported speech the present simple 'come' shifts back to the past simple 'came'. The word order is also statement order after 'where'.