在下列各句的空白处填入一个适当的词，使句子意思完整、语法正确。

1. How q______ time passed. I've been in my hometown for two months.

2. It's our d______ to protect (保护) the environment.

3. I think this dictionary is h______ for your study.

4. Hurry up, or we won't c______ the early bus.

5. Don't be scared to make m______ when you speak a foreign language.