题干
阅读判断。
This is my day
I am a doctor. I work at night. I go to work at 6:30 p. m. I eat dinner at 9:30. I usually go home at 8:00 in the morning. After breakfast, I go to bed at 9:10 a. m. I usually get up at 2:30 in the afternoon. I eat lunch at 3:00 in the afternoon. Then I play sports at 4:00 in the afternoon.
This is my day. I enjoy my life.
点为半圆弧的圆心，
.电荷量相等、符号相反的两个电荷分别置于M、N两点，这时
