1. be yourself 行为自然；不做作

The best thing you can do is to go into the interview and just be yourself.

你最明智的选择就是进去面试时自然地表现自己。

2. (all) by yourself 独自地

I'm amazed you managed to move those boxes all by yourself.

你居然能一个人搬动那些箱子，真让我吃惊。

3. (all) to yourself 独有；专用

So you have the whole house to yourself this weekend?

那么，本周末整个房子就是你一个人的天下了？

4. in yourself

这个短语用于询问某人身体抱恙时的自我感觉。

I know you must still be uncomfortable, but how are you in yourself?

我知道你肯定还是不舒服，不过你自己感觉怎么样？

5. help yourself to 自取； 随便吃

You are asked to help yourself to food.

请你自取食物。

这个短语让我想到了一句作文加分句：

God helps those who help themselves.

天助自助者。

6. let yourself go

这个短语有两个意思，第一是放任自流；不修边幅。

It's easy to let yourself go when you've got small kids.

有了小孩后很容易就不注意打扮了。

第二是完全放松，尽情享受。

It's a party - let yourself go!

这是个聚会——尽情地玩吧！