Exercise 1:

1. Yesterday evening Tom had a bath when the phone rang. He got out of the bath and answered the phone.

2. I saw Tony in the park. He was sitting on the grass and reading a book.

3. While I was walking in the garden, I hurt my back.

4. Tommy burned his hand when he was cooking the dinner.

5. George fell off the ladder while he was painting the ceiling.

6. Last night, I was reading in bed when suddenly I heard a scream.

7. Were you watching television when I phoned you?

8. Ann was waiting for me when I arrived.

9. I was not driving very fast when the accident happened.

10. I broke a plate last night. I was doing the washing-up when it slipped out of my hand.

cho tam giác ABC vuông ở A, đường cao AH.

1) Chứng minh tam giác ABH đồng dạng tam giác CAH và AH^2 = BH.CH

2) BH=4cm; CH=9cm. Tính AH; AB