乒乓球运动中,一场比赛应连续进行,但在局与局之间任何一名运动员都有权要求不超过()分钟的休息时间。
A.2
B.3
C.4
D.5
参考答案:A
解析:任何一名球员休息时间不超过2分钟。
When asked why he went there, he said he was sent there _____for a space flight.
A.training
B.being trained
C.to have trained
D.to be trained
紫外线进行灭菌时,其灭菌力最强的波长是
A.250nm
B.251nm
C.52nm
D.253nm
E.254nm