衬套技术要求：其外层高出固定螺钉不小于（）毫米。
A、2
B、4
参考答案：A
_______her home, Mary helps her mother with some housework. [ ]
A. As soon as she returns
B. On arriving
C. After she gets
D. Instantly she reaches
中国人民银行从银行间外汇市场购入外汇时，相应会（）基础货币。
A、回笼
B、购入
C、买断
D、投放
