催化剂中毒的两种极端情况是（）。A、均匀中毒和孔口中毒 B、均_爱下问搜题

搜题请搜索小程序“爱下问搜题”

问题单项选择题

催化剂中毒的两种极端情况是（）。

A、均匀中毒和孔口中毒

B、均匀中毒和一次性中毒

C、一次性中毒和孔口中毒

D、物理性中毒和孔口中毒

答案

参考答案：A

选择题

已知等差数列{a_n}的前n项和为S_n，且a₃+3a₆+a₉=15，则S₁₁等于（　　）

A．78

B．66

C．55

D．33

选择题

— Do you think he can get the first prize for jumping?
—Impossible now. He to do so, but he has just hurt his leg.

A. would expect
B. was expected
C. has expected
D. is expected