The research on the new bird flu virus vaccine ischallenging and demanding Who do you think can do the job–________ my students have a try

_____ I cannot understand is _____ she wants to resign her present job.

Li Lei _____knew any Japanese, did he

The students are listening to the teacher with their eyes the blackboard [ ]

In the dark I could see a man lying on the floor, ____up with rope, which was____.