The four word you should learn

1. Yes

2. No

3. (I) Don't understand

4. (It's a )Good question. I need more time to think (it).

(from Sam)

1. 是的，好的，可以

2.不是，不好，不行

3.不明白，没听懂

4.这个问题很好，但是我得花点时间好好想想/好好考虑考虑