腻子的刮涂分为补刮、满刮和（）等方法。
A.软硬交替刮
B.干刮
C.湿刮
D.平刮
参考答案：A
铸造固定桥桥体常采用的焊接方法是（）
A.转移焊接法
B.前焊接
C.后焊接
D.离模焊接法
E.连模焊接
A huge amount of oil was spilt on the East Sea, the causes of_____ are still under investigation. [ ]
A. it
B. that
C. which
D. whom
