句型转换。

1. Mr. Green likes playing tricks on others. (同义句)

    Mr. Green likes playing _______ _______ on others.

2. Christmas Day is December 25th. (对划线部分提问)

    _______ _______ is Christmas?

3. He comes back. I tell you at once. (改成条件状语从句)

    If he _______ back, I _______ you at once.

4. I found many candies and toys in it. I got up in the morning. (用when合并两个句子)

    _____________________________________________________________.

5. Is there any interesting festival in your hometown? (作肯定回答)

    ______________________________________________________________.

人体骨髓腔内开始出现黄骨髓是在（）。

A、胎儿后期

B、出生前后

C、1岁左右

D、5岁左右