供全分析及单项分析用的水样量各为多少?
参考答案:
供全分析的水样大于5L,若水样浑浊,应分装两瓶.供单项分析用的水样应大于0.3L,采集水样的数量应满足试验和复核的需要。
— Look! Somebody ________ the sofa.
— Well, it wasn't me. I didn't do it. [ ]
A. is cleaning
B. was cleaning
C. has cleaned
D. had cleaned