中国森林2008年的覆盖率是多少？

A. 正确
B. 错误

A. Each B channel can transmit up to 64 kbps
B. The ISDN B channel carries voice or data
C. The ISDN D channel transmits control information.
D. The D channel transmission rate varies depending on the service used.
E. HDLC or PPP can be used to encapsulate D channel information.

A. 直线式
B. 弧形
C. 斜线
D. S型