My favorite _____ is Monday.

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?

cannot smile like a child, __________ a child smiles with hiseyes, while a man smiles with his lips alone.

_____ the chapter four times, and Ifinally understand the author’s theory．

They have ______ a plan for reducing the budget deficit(财政赤字), which is quite practical.