阅读理解。 One day, Tim goes home from schoo
问题：
阅读理解。
One day, Tim goes home from school and says to Mother Cat, "Please take
your children to the park near here. You can play there. But don't forget there are
five cats in the park."
Mother Cat is very glad. She takes her four children to the park soon. Now
they are playing happily.
Mother Cat is counting the number of the cats, "one, two, three, four …"
Mother Cat is worried (着急). "There are five cats here. But now there are only
four cats. What can I do?"
Mother Cat is crying (哭). She is looking for the fifth cat. "Where is it?" Oh
dear! Where is the fifth cat?
1. Mother Cat has _____ children.
A. 2
B. 3
C. 4
D. 5
2. Mother Cat is crying because (因为) _____.
A. she can't find the fifth cat.
B. she can't find home.
C. Her children are not in the park.
D. she forgets the time to go home
3. The fifth cat is _____.
A. in the river
B. at home
C. Tim
D. Mother Cat
和内电阻
，实验器材有：一只DIS电流传感器（可视为理想电流表，测得的电流用
表示），一只电阻箱（阻值用
表示），一只开关和导线若干。该同学设计了如图甲所示的电路进行实验和采集数据。
（用
—R图像，则由图像可求得，该电源的电动势