15.---Tom is never late for work. Why is he absent today?---Something ________ to him.
He seized me ___ arm.
—____busy schoolwork,the children also have to take arts,music and sports classes in their free time.—I wonder what they will become.
How can you expect to get anything____ you never give?
There are many kinds of birds in Australia,and over 140 species of snakes,many of ____are extremely dangerous.
Private cars are required to take turns off roads one out of five weekdays ____the traffic pressure.