串级数为3级的试验变压器串级装置的容量利用率为（）
A.1
B.1/2
C.1/3
D.1/4
参考答案：B
Read and choose.选出适当的单词补全句子。（只填序号）
1. I have a ____.
2. This is a ____.
3.There are forty ____ on the farm.
4. This ____ is white.
The workers in HuaShan Mountains have to rubbish to keep the mountains clean.
A．turn up
B．pick up
C．mix up
D．give up
on the farm. 
is white.