译出句中汉语部分，使句意完整（要求用不定式）。

1. It’s our duty （搞好学习）

2. It’s very kind of you （帮我儿子学数学）

3. (怎样才能说一口漂亮的英语) is clear.

4. （到哪儿去找丢失的孩子）troubles all the policemen.

5. It will be a mistake (我们不去帮他)

6. My happiness is (为大家的幸福而工作)

1. It’s our duty to study well.

2. It’s very kind of you （to help my son with his math）

3. (How to speak english excellently) is clear.

4. （Where to look for the lost child）troubles all the policemen.

5. It will be a mistake (for us not to help him)

6. My happiness is (to work for your happiness)