—The research on the new bird flu virus vaccine is challenging and demanding. Who do you think can do the job?—____ my students have a try?
----Sorry, I have broken your bike. ----I’ll try to get it _______.
----It is true that he is in trouble at this moment. But I don’t think he will give up. ----I quite agree with you. He is a ________________person.
There was ________ time _________the English language was based more on German.
At the meeting they discussed three different _________ to the study of mathematics.
Look! Here come the dark clouds. It______ rain.