It was not until I came here ________ I realized this place was famous for not only its beauty but also its weather.(2012·湖南)

We should do ____ to stop sandstorms（沙尘暴）from happening again andagain.

Did Jenny clean her house yesterday—She _______ because she was not quiteherself.

He is _____ Australia boy.

Only when the teacher walked into the classroom ________ that she had left the speech note at home.