What’s the radio saying, Jack—Oh, ______ meteorolite(陨石) attacked _______ earth and it fell down in Russia on February 15, 2013.

______ difficulties we may face in our life, we shouldkeep calm and take measures to get them over.

I think Tom, as the head of a big department, should cither study regularly or______his job. [ ]

What do you think of teacher，Bob?—I find it fun and challenging.It is a job ________ you are doing something serious but interesting.

I can’t carry the luggage. It’s so heavy.— Why not have someone strong enough_______ you a hand then