不影响52型真空泵轴承的部分是()。
A.电动机
B.联轴器
C.填料压盖
D.键
参考答案:C
I see from the information you have sent me ______ you come from London. [ ]
A. which
B. that
C. who
D. what
种子燃烧后,剩下的灰烬是______.