蓄电池室内照明线宜采用穿管暗敷,室内不应装设()。
参考答案:开关和插座
Mr. Black has ___________China for nearly two months.
A.been to
B.come to
C.gone to
D.been in
一个多边形的边数增加2条,则它的内角和增加( )
A.180°
B.90°
C.360°
D.540°