根据句意，用所给动词的适当形式填空。She wonders if there _______(be) a flower show next week.
At last several of the runners ________(fall) behind in the race.
Jack devotes as much time as he can to__________(help) others.
The railway ________(connect) Qinghai to Tibet is the longest plateau (高原) railway in the world.
If you _______(not be) careful enough when crossing the road a car may hit you.