不适宜频繁操作的断路器是（）
A.六氟化硫断路器
B.真空断路器
C.少油断路器
D.弹簧储能断路器
参考答案：C
单句改错。
1. How much percentage of his income is taxable (可纳税的)?
______________________________________________________
2. An increasing percentage of the population owns their own cars.
3. The most percentage of the people are against the plan.
天竺葵的黄白色叶片用清水冲洗后，滴上碘液，没遮光的部分变成______这证明细胞内产生了______．
