–What do you think of teaching, Bob?–I find it fun and challenging. It is a job ___ you are doing something serious but interesting.
I like _____ in spring when everything turns green and active.
You can imagine what difficulty we had __________ home in the snowstorm.
We hurried to the station, ________ the train was gone.
.Operation rooms should be kept free ______ bacteria of any kind.
.The League Secretary and monitor ______giving a speech while the rest of the class ________ listening attentively.