下列简单机械中，定滑轮、扳手、筷子属于省力杠杆的是____ ；一台起重机将重3600N的货物提高5m的过程中，货物的重力势能____ （填“增加”、“减少”或“不变”），如果总功为30000J，则起重机的机械效率为　____ 　．

当你遇到某同学说谎、不诚实的时候，你可以用下列哪个故事来帮助他（    ）

A: Good afternoon, Jim.

B: Good afternoon, Alex.  ____?

A: My birthday is on May 3rd.____?

B: My birthday is on November 27th.

A: Oh, today is your birthday, right?

B: Oh! I forgot(忘记) it.

A: ____You can call our friends -- Jenny, Mike and Bob. And we can have dinner at your home.

B: That's great. But I forgot Jenny's telephone number.____?

A: It is 365-4052.

B: ____?

A: I think pizza (披萨) is great, and we can go to the store to buy a birthday cake and some fruit.

默写古诗《竹石》

____ ，____ 。

____ ，____ 。