生物性有毒有害物质的毒性
A．包括一般毒性和特殊毒性
B．主要产生神经毒性
C．主要引起过敏反应
D．主要是致癌性
E．毒性一般低于环境污染物
参考答案：A
— Alice told me you called yesterday.
— Yes, I had a problem with Jane, ___________I thought you could help me with, but you were not in.
A．who
B．whom
C．that
D．which
蒸汽管道暖管有何意义？如何进行暖管操作？
