问题

Experts have been warning _____ of the health risks caused by passive smoking[ ]
A: at a time
B: at one time
C: for some time
D: for the time
B: at one time
C: for some time
D: for the time
正确答案是:
同类题型
It is very ______ that she will ring metonight.
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ane is lucky to have got the well-paid job.一Yes, __she is inexperienced and young.
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