问题
选择题
The old woman has two sons, one ______ is a teacher. [ ]
A. of who
B. of whom
C. of which
D. of them
答案
答案：B
搜题请搜索小程序“爱下问搜题”
The old woman has two sons, one ______ is a teacher. [ ]
A. of who
B. of whom
C. of which
D. of them
答案：B
下表为某电烤箱铭牌的部分参数，其简化电路如图所示R1、R2均为电热丝．求
（1）当开关S闭合时，电烤箱处于______温挡．当电烤箱在高温挡工作时，1min消耗的电能是多少焦耳？
（2）求R1和R2的电阻各是多少？
| 额定电压 | 220V | |
| 额定功率 | 高温挡 | 1100W |
| 低温挡 | 440W | |
