第三宇宙速度是指在地球位置对什么的逃逸速度（）？
A、地球引力
B、月球引力
C、太阳引力
D、木星引力
参考答案：C
— Do you think he will come to my birthday party?
— _________.
— That's good. Everybody's expecting him. [ ]
A. You can count on it
B. I don't know for sure
C. You can believe him
D. It depends
抗盐生产使用的是（）。
A、SPAN-20
B、SPAN-40
C、SPAN-80
D、SPAN-120
