与Cable Modem相比，ADSL的优势主要是（）。
参考答案：网络拓扑结构先进
若x，y是变量，且y=（k-2）x|k-1|是正比例函数，则k值为______．
The teacher asked the girl again, raising his voice a bit, but still _____ no answer.
A. receiving
B. received
C. receive
D. to receive
