John didn’t feel well yesterday; otherwise he ______ to see his friend off at the airport.

—Daddy, can you buy me a new MP3 when you go to Beijing? —You ______ get one if you are admitted to a key middle school.

(2013·高考北京卷)If we________a table earlier，we couldn’t be standing here in a queue.

The weather turned out to be fine yesterday．You __the trouble to carry your raincoat with you．

—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?