Many parents happily pay a lot of money, only ______ the tours are not rewarding enough for their children.

It was so bright outdoors that we could see clearly what was happening through the curtains ________ before the window. 

Lily’s mobile phone was left in a taxi accidentally，never______again.

When ____ to danger and conflict, men tend to increase blood pressure, ______ nervous and  anxious.

The teacher asked us_______ in deep water