When and where to build the new factory ______ yet.

单项选择题To our surprise, the stranger ______ to be an old friend of my mother's.

单项选择题The police still haven' t found her, but they' re doing all they（）

A. may
B. can
C. must
D. will

单项选择题It was the doctor's carelessness that ______ the serious accident.

单项选择题How much ______ she looked without her glasses!

单项选择题The air of countryside is cleaner than ______ of city, but I don't like to live ______ far.