Eye doctors recommend that a child’s first eye exam ________ at the age of six months old.
We offered him our congratulations ________his passing the college entrance exams.
The doctor will be free ________.
The train leaves at 6:00 p.m.So I have to be at the station ________5:40 p.m.at the latest.
I must thank my parents ________to be a college student.
People living in the area where there is a lack of electricity often keep a supply of candles ________power failure.