A：Are
B：Is
C：Am
下列关于人类性别决定的叙述，正确的是（ ）
补全对话, 其中有两个多余选项。
A: Hello! This is Tom speaking. ____
B: Sorry, Jack is out at the moment.
A: ____
B: This is Jack’s mother.
A: Hello! Mrs Brown. ____
B: Of course. ____
A: That’s very kind of you. Would you please tell Jack we will have a party about stamp collection this Sunday morning?
B: Oh, a party about stamp collection on Sunday morning. OK, ____
A. Who's speaking, please?
B. Hold the line, please.
C. Can you take a message for me?
D. Can I take a message for you?
E. I'll tell him as soon as he comes back.
F. Could I speak to Joe, please?
G. Could I speak to Jack, please?
光射到平面镜上，入射角为45º，反射角为（ ）
