在卧式铣床上用刀杆和刀杆垫圈装夹刻线刀具,刀杆垫圈的要求之一是()。
A.较大的孔径
B.较小的孔径
C.较大的厚度
D.较高的端面平行度
参考答案:C
表现为与语言、声音、呼吸关系最为密切的是()
A.元气
B.肺气
C.宗气
D.中气
E.心气
Mr. Green _______ to the manager now. You'd better call him later. [ ]
A. talk
B. talked
C. is talking
D. was talking