根据括号内的要求改写下列句子。

1. I don't know Japanese, so I can't talk to the Japanese. (改为同义句)

    ________ I ________ Japanese, I would talk to the Japanese friends.

2. I was so anxious that I couldn't sleep. (改为同义句)

    I was ________ anxious ________ sleep.

3. He didn't realize the dangers of the situation at all. (改为同义句)

    He didn't realize the dangers of the situation ________.

4. We should allow twenty - year - olds to drive a car. (被动语态)

    Twenty - year - olds ________ to drive a car?

5. If I don't permit, you can't use my dictionary. (改为同义句)

    You can't use my dictionary ________.

当事人订立合同，要经过要约、承诺。下列文件中，构成合同要约的是（）。

A.招标公告

B.投标文件

C.宣传广告

D.招股说明书