提出大陆漂移假说的德国科学家是[ ]
A．麦哲伦
B．哥白尼
C．魏格纳
D．哥伦布
答案：C
— John, my computer doesn't work.
— Why not ask Mr Liu _____ it? [ ]
A. to buy
B. not to buy
C. to check
D. not to check
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