3) Lose - lost

Make - made

Put - put

See - seen

Take - taken

4) 1. Nobody has sent me a text message this week.

2. Look - Sarah has dyed her hair!

3. Sorry. I have not finished my homework.

4. Have you bought that new CD?

5. Oh no! I have lost my mobile again.

5) 1. You should find something interesting to do.

2. You shouldn't eat more packets of crisps today.

3. You should pay more attention in class.

4. You should get a job.

5. You should buy him a new one instead.