GW6-220型母线隔离开关动、静触头之间的最小电气距离不应小于下列何值
A.1800 mm;
B.2000mm;
C.2550mm;
D.3800mm。
参考答案:C
南温带与南寒带的分界线是( )
A.66.5°S
B.66.5°N
C.23.5°N
D.23.5°S
用be动词的适当形式填空。
1. My name _____ Jack.
2. She _____ Julia Roberts.
3. I _____ a girl.
4. Tom and Mark _____ good friends.
5. _____ you a teacher?