水利工程造价工程师在注册证书有效期内,其注册内容发生变化,应当在发生变化后()内,到规定的受理机构办理注册变更手续。
A.3个月
B.2个月
C.4个月
D.6个月
参考答案:B
The fact _____ the mainland of Great Britain is made up of three kingdoms _____still unknown to many.[ ]
A. which, is
B. that, is
C. which, are
D. that, are
Y146型光电长度仪器测量距梳子根部6.3mm,梳子终点位置的光电流约为()。
A、80
B、90
C、70
D、100