Beijing was under an “orange” smog alert on Feb. 24, which marks the first time the second-highest warning level of a new system introduced last year________.
A.has been raised | B.raised |
C.has risen | D.rose |
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Beijing was under an “orange” smog alert on Feb. 24, which marks the first time the second-highest warning level of a new system introduced last year________.
A.has been raised | B.raised |
C.has risen | D.rose |