B-19：blow hot and cold 出尔反尔

A：Look! The girl is so beautiful and she is smiling at me. She is lovely!

A: 看!那个女孩真漂亮，她对我笑呢。她真是可爱!

B: I can't agree with you. She's pretty, but she always blows hot and cold.

B：我不同意你的看法。她是很美，但她也总是喜怒无常。

A: What makes you think so?

A：你怎么会这么认为?

B: She's my sister, you know.

B: 你知道吗，她是我的妹辣。