在铣床上刻线,若刀具几何角度刃磨正确,影响刻线清晰度和直线度的因素之一是()。
A.刀尖损坏
B.刻度盘松动
C.分度错误
D.进给量较小
参考答案:B
— Which of the three optional courses did you like best, Joe?
— To tell you the truth, I didn't like _____ of them. [ ]
A. either
B. both
C. any
D. neither
与同纬度的长江中下游平原相比,青藏高原气温日较差大的原因为()
①青藏高原距离太阳近
②青藏高原比长江中下游平原太阳高度角大
③地势高,空气稀薄
④白天太阳辐射强⑤云层厚⑥夜晚大气逆辐射弱
A、①②③
B、④⑤⑥
C、③④⑥
D、②⑤⑥