零序电流保护，能反映各种不对称短路，但不反映三相对称短路。
参考答案：错
按要求改写句子。
1. Jenny can play the piano. (改为否定句)
_________________________________________________________
2. I sometimes walk to school. (同义句)
3. This isn't a new dress. (复数)
4. These are men. (改为单数句子)
5. Here are many dresses. (改为单数句子)
6. It's a square. It's a rectangle. (合并为选择疑问句)
直接写出结果．
45÷5×9=
8×7÷2=
134-76+66=
4×9÷6=
75×6÷5=
44+56-73=
300-102=
72×6÷9=
101-34-26=
