It’s quite normal to ten percent of the cost of a building for a period of six months or so, in case faults are found in it.
Be careful when you cross this busy street. ________, you may get run over by a car.
Smoking is so harmful to people’s health that it kills __________ people each year than automobile accidents.
I’ll come to pay a visit to you if _______ this weekend.
The student was_______ a gold cup for his excellent performance in the competition.
Tom ____ be ill, for I saw him playing basketball an hour ago.