乙烯进料量相同条件下,随着催化剂选择性的提高()加入量相应降低。
A、氮气
B、甲烷
C、氧气
D、抑制剂
参考答案:C
秦岭——淮河一线的1月份平均气温大约是[ ]
A.8℃
B.0℃
C.-8℃
D.-24℃
The fact that many college graduates get lower pay than some workers has ______ a heated discussion.
A.set out
B.set about
C.set up
D.set off