The TV drama _________ the north of China during the anti-Japanese war. [ ]

How can you expect him to make any progress ________ you never give him a chance to have a try?

Every means ______ tried, yet no result ______encouraging up to now

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?

Can you finish ________ these books before 10 o’clock ——Yes, I can.