Man: Mr. Brown asked me to tell you that he’s sorry, he can’t come to meet you in person. He’s really too busy to make the trip.
Woman: That’s OK. I’m glad you’ve come in his place.
Question: What do we learn from the conversation().

A. The man is late for the trip because he is busy.

B. The woman is glad to meet Mr. Brown in person.

C. The man is meeting the woman on behalf of Mr. Brown.

D. The woman feels sorry that Mr. Brown is unable to come.

质点是常见的物理模型，下列机械运动所涉及的研究对象中，分析正确的是（）

A.研究汽车在平直公路上行驶时，汽车可视为质点

B.研究地球自转时，地球可视为质点

C.研究月球绕地球作圆周运动时，月球不可视为质点

D.研究挂钟上分针、时针的转动时，分针、时针可视为质点