催化裂化催化剂应控制的杂质含量有()。
A.氧化钠
B.氧化铝
C.氧化铁
D.硫酸根
参考答案:A, C, D
________, the pay isn’t attractive enough, though the job itself is quite interesting.
A.Generally speaking
B.On the contrary
C.In particular
D.To be honest
试述常见的腹腔脓肿及其治疗原则。