填写《线路允许速度表》数据时,各速度区段和限制慢行地段应根据里程大小,()顺序填写。
A.由小向大
B.由大向小
C.由远至近
D.由近至远
参考答案:A
— Bob didn't pass this exam.
— He _____. [ ]
A. should study hard
B. should have studied hard
C. should be studying hard
D. study hard
制备滴丸常用的冷凝液有()、()、二甲硅油和水等。