火炬筒及排气筒除可用钢板卷制而成，也可以用无缝钢管和（）制成。
A.合金钢管
B.不锈钢管
C.焊接钢管
D.镀锌钢管
参考答案：B
—Mom’s gift? She _____ have chosen a better one for me.
—She must be very happy to know it.[ ]
A. should
B. might
C. couldn't
D. mustn’t
猝死
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