青霉素的毒性作用主要是通过（）
A.Ⅰ型变态反应
B.Ⅱ型变态反应
C.Ⅲ型变态反应
D.Ⅳ型变态反应
E.都不是
参考答案：A
The National Education Department says that school safety has set off alarm bells with frequent reports of serious accidents ________ students got injured or killed.[ ]
A. that
B. in which
C. by which
D. for which
将60ml的硫化氢和75ml的氧气混和后,在一定条件下反应，直到反应物之一耗尽,则同温同压下，生成二氧化硫的体积是:
[ ]
A、50ml
B、45ml
C、40ml
D、35ml
