用高效液相色谱法测定粮、油、菜中西维因残留量时,所用的检测器是()。
A.紫外检测器
B.示差折光检测器
C.电导检测器
D.光导检测器
E.荧光检测器
参考答案:A
The E-mail Jack had looked forward to ______ last night at last and he was very happy.
A.arrived
B.arriving
C.had arrived
D.arrived
平衡挂线时,不得在()进行其他作业
A.同一相邻耐张段的同相(极)导线上
B.不同相邻耐张段的同相(极)导线上
C.同一相邻耐张段的异相(极)导线上
D.不同一相邻耐张段的异相(极)导线上