高炉的煤气利用一般在()之间。
参考答案:40%~50%
Her tears ______ fast when Margret heard of the bad news that her husband died in the battle against Iraq.
A.flew
B.flowed
C.fled
D.fell
用ICP-AES法测定金属元素总量时,对于污水应取含悬浮物的均匀水样,对于地表水应待自然沉降()min后,取上层非沉降部分分析。
A.20
B.25
C.30
D.35