遗传物质的载体是一种叫_______有机物，主要存在于细胞的________里面。

用所给单词的适当形式填空。

1. Look, it's ____________ (cloud) now. I think it's going to rain soon.

2. Song Zuying is a ____________ (sing).

3. Are there any interesting ____________ (activity) this evening?

4. He ____________ (not live) in Paris.

5. I like dogs because they are ____________ (friend) to people.