直接式选针是通过选针机件直接作用于（）来进行选针
A.针踵
B.针杆
C.针头
D.针槽
参考答案：A
____________ your father saw you, what would he say?
A. If B. Suppose C. Unless
仪表伴热、绝热保温有哪些作用？
