船舶施放三长一短声的应变信号是表示：
A. 左舷有人落水
B. 右舷有人落水
C. 人员落水
D. 都不是
可用于测定路基土方最佳含水量的试验方法是()
A. 灌砂法
B. 环刀法
C. 重型击实实验法
D. 核子密度湿度仪法
By the end of the year all but two people _____.
A. have left
B. will be leaving
C. will leave
D. will have left
It is desired that she _____ to teach us at least twice a week
A. comes
B. would come
C. come
D. will come
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