— Look at the sign “No smoking!” You smoke here.
— OK. .
A:can't; I won't
B:mustn't; I will
C:won't; It doesn't matter
D:mustn't; I won't
在电风扇、电熨斗、电磁起重机、动圈式扬声器、动圈式话筒和发电机这些装置中,利用电磁感应原理工作的有____ 、____
读图,回答问题:
用电高峰时期,家庭里的白炽灯泡比正常发光要暗一些.这是因为,在用电高峰时( )