It's not that..., but... 不是因为……而是因为……用法透视这是一个对称句型，表示“不是因为……而是因为……”才干什么。

      1. It's not that I don't like the car, but I think it is too expensive.

　　不是我不喜欢这辆车，而是它太贵了。

       2. It's not that I am unwilling to help you, but I'm tied up with extra work these days.

　　不是我不愿意帮你，而是因为这段时间我工作太忙了。

       3. It's not that he doesn't need your help, but he thinks it will be an inconvenience to you.

　　不是他不需要你帮忙，而是他怕给你带来麻烦。会话记忆

       A: You have to finish your dinner before you leave the table.

　　你离开饭桌之前必须把饭吃完。

       B: But, Mom, I can't eat anymore. I'm stuffed.

　　可是妈，我吃不下了，我饱了。

      A: What's the matter? It doesn't taste good?

　　怎么了。不好吃吗?

      B: It's not that I don't like your cooking, but I ate some cookies before we had dinner.

　　不是我不喜欢你做的饭，而是我在晚饭前吃了些曲奇。