国际上高空情报区的英文缩写为：（）.
A.FIR
B.UIR
C.CTR
D.TMA
参考答案：B
I carried the bowl with both hands________, so that I wouldn’t break it.[ ]
A. carefully
B. happily
C. quickly
D. carelessly
二次沉淀池是用来去除在生物反应器中增殖的生物细胞物质
