【简答题】若用重组质粒转化大肠杆菌,一般情况下,不能直接用未处理的大肠杆菌作为受体细胞,原因是______ _______________________________________。
【简答题】A.included B.contained C.composed D.consisted
【单选题】在C#语言中定义了如下变量:char ch;下列赋值语句正确的是(选一项)
【单选题】(The atmosphere) (is consisted) of certain gases (mixed together) (in) definite proportions.
【简答题】A.stuck B.strung C.rung D.consisted