唐氏综合征的实验室检查不妥的是()
A.染色体检查
B.红细胞SOD-I活性检测
C.白细胞碱性磷酸酶检测
D.B淋巴细胞转化反应检测
E.痰液胸腺因子水平检测
参考答案:D, E
________full preparations, we decided to put off the meeting till the next week. [ ]
A. We did not make
B. We had not made
C. Not having made
D. Having not made
造成加氢装置反应器床层压降上升的原因可能有()。
A、催化剂积炭
B、催化剂破碎
C、床层由于粉尘而堵塞
D、循环氢减小