波形补偿器属于()补偿。
A、管子
B、自然
C、方形
D、人工
参考答案:D
A bridge must over the river. [ ]
A. makes
B. being made
C. build
D. be built
The boy became fatter and fatter each day and ___made his parents sad.
A.which
B.what
C.he
D.it