caahexy

例句：

1. 1. I don't knowwhat happened to my phone.
   我不知道我的手机怎么了。
2. 2. She didn't know how tofix the car.
   她不知道如何修理汽车。
3. 3.We didn't know if it wouldrain or not.
   我们不知道是否会下雨。