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?

After visiting the science museum, the students don’t doubt _________

East of the mountain ______ two towns, ________ my hometown.

What time will Mr. Brown be back to China – Sorry, I don’t know______.

There is no way he can make a _______ when he leaves school now， I think.