若每条HW线均为PCM基群，则HW2TS5位于复用线上的TSX，其中X=（）
A.74
B.73
C.42
D.41
参考答案：C
若cosα+cosβ+cosγ=sinα+sinβ+sinγ=0，则cos（α-β）=______．
阅读课本P44 的课文，回答下列问题。
1. What game are Jenny and Danny playing?
________________________________________
2. What number does Jenny choose?
3. Who is good at this game?
4. Can Danny spell the word "green"?
5. Does Jenny get good advice at last?
