受热面管子安装前,焊缝质量应做无损探伤抽查,在制造厂已做100%无损探伤的,则按不同受热面的焊缝数量抽查()。
A.1/1000
B.2/1000
C.5/1000
参考答案:C
Science is more than a collection of unrelated facts; to be meaningful and valuable, ______ must be arranged to show generalized character.
A.which
B.those
C.it
D.they
布洛芬含量测定中溶解样品的溶剂是()
A.对甲基橙指示剂显中性的乙醇
B.水
C.对酚酞指示剂显中性的乙醇
D.对甲基橙指示剂显中性的甲醇
E.对酚酞指示剂显中性的甲醇