ce Craven, adoctor from the USA, is the author of several published reports, one of _______introduced the idea in 1953 _______ aspirin could reduce the risk of heartattacks

I’d ______ the operation unless it isabsolutely necessary

_____,he can be fluent in English.[ ]

The work is _________ ,so I often feel ________.

Do you enjoy Han Lei’s songs— Yes. He is the winner of I am Singer II. I can’t think of anyone with a ____ voice.