单位工程有见证取样和送检要求,随机抽样送检的次数应为该项目规定试验总次数的( )。
A.20%
B.25%
C.30%
D.35%
参考答案:C
Where is my bag? It's _____________ the desk. [ ]
A. in
B. behind
C. on
蝶类和蛾类有什么区别?