若用一个开关同时控制两盏电灯,下列说法正确的是 ( )
A:两灯一定是并联
B:两灯一定是串联
C:两灯既是并联也是串联
D:两灯可能并联也可能串联
直角三角形纸片的两直角边长分别为6,8,现将△ABC如右图那样折叠,使点A与点B重合,则折痕BE的长是( )
⑴____A. morning B. good C. afternoon
⑵____A. friend B. sister C. brother
⑶____A. this B. I C. you
⑷____A. is B. am C. be
⑸____A. he B. she C. my