1. It can't be Ms Nhi you saw,she is in Hanoi.

2.  I have never played game of water-polo before. 

3. He is said to escape in a stolen car.

4. I wouldn't have been getting wet if I had taken an umbrealla.

5. It was such a expensive trainning course that I can't afford it.

1. must not be ridden

2. is worth to ask

3. no notice of his doctor's

4. was amazed to find that

5. was too high for

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1. It can't have been Ms Nhi because she's in Hanoi.
2. I have never played game of water-polo before.
3. He is said to have escaped in a stolen car.
4. I wouldn't be getting wet if I had taken an umbrella with me.
5. It was such an expensive training course that I couldn't afford it.

B/
1. Bicycles must not be ridden on the station platform.
2. It's not worth asking George to help.
3. Mathew took no notice of his father’s advice.
4. Alan was amazed to find that the passport was closed when he arrived
5. The top shelf was too high for the children to reach.