造成再沸器蒸汽加不进原因是（）。
A、塔釜没有液位
B、凝液罐倒淋没关
C、再沸器不凝气多
D、蒸汽阀没有全开
参考答案：C
By the end of last month, we had sold _______ as we did last year. [ ]
A. as twice many cups
B. twice cups as many
C. twice as many cups
D. as many cups twice
对象限角描述时，下列描述正确的是（）。
A.E23°S
B.N23°W
C.W23°N
D.W23°S
