During the period of recent terrorist activities, people _____ not to touch and unattended bag.
__________ it rain, the crops_____________.
--You forgot your keys when you left home in the morning. --Good heavens,___________.
It is impossible for ______ little children to do ______ much work in ______ a short time.
This new-type machine____________ little room.
--You don't look so well, Mary. What's the matter with you? --Why?___________.