How do you like the set of popular science books?——Wonderful! It _____ many problems we are interested in exploring.

The little girl is not quite confident ____ her ability to go to a key university and she is very sensitive _____ anything concerned with it.[ ]

It is dark outside, so please____ your step while going down the stairs.

It was not a good idea to go skating. You __________your leg.

The boss commanded that the task _____ before 5 o’clock this afternoon. [ ]