In a sport team each player has a clear role, and there are few occasions ______ members are confused or uncertain of their roles.

（2014年山东日照市高三校际联合检测）9．He didn’t tell his wife about buying a new car for her_____he could give her a big surprise on her birthday．

It’s May 4th.

. Some of the suspects ________ refused to answerand kept their mouths shut.

She is going to ____ the plane to Beijing.