图1-2-40所示电路中,当R电阻获得最大功率时,它的大小为()Ω。
A.2.5
B.7.5
C.4
D.5
参考答案:D
选择和画线部分单词意义相近的选项。
1. Thank you for your message.[ ]
A. information
B. news
C. letter
2. Although I still make a lot of mistakes, it doesn't bother me like it used to.[ ]
A. Then
B. However
C. Though
3. It is very delicious.[ ]
A. well
B. better
C. tasty
4. You should always keep your hands, but not your elbows, on the table.[ ]
A. at
B. in
C. above
5. I don't find them so strange any more.[ ]
A. more
B. any longer
C. much
The old lady can't ______ her cold in a few days. [ ]
A. get
B. go over
C. get out
D. get over