X线防护的目的，正确的论述是（）

A.防止发生有害的非随机效应

B.将非随机效应发生率限制到可接受水平

C.防止有害的随机效应发生

D.防止工作人员受到任何辐射

E.降低受检者检查频率

Mike has put on so much weight this year that his mother has to ________ all his trousers to his measure.[ ]

A. let out  

B. give away

C. bring in  

D. lay out