一般来说，北方的群落中，优势种的数目比南方的( )。
A. 多
B. 少
C. 相等
D. 看具体情况而定
Secretary Leavitt stressed（）in the process of fighting H5N1 bird flu virus.
A. research and development of new medicine
B. new devices of prevention
C. separation of infectors
D. surveillance and information exchange
On that bitterly cold winter night, few people walked along the now （）narrow street.
A. deserted
B. lonely
C. isolated
D. neglected
Some European retailers warned that they would （），if their stock isn't released soon.
A. close their stores
B. resort to legal action
C. take on a strike
D. take some violent actions
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