-- You can use MSN to talk with Vivien on the InternetI know. But can you tell me ?A

问题补充：

-- You can use MSN to talk with Vivien on the Internet.

--- I know. But can you tell me ?

A. when I can use it

B. what I can use it

C. why can I use it

D. how can I use it

答案：

(答案→)A. when I can use it

B. what I can use it

C. why can I use it

D. how can I use it

解析：本题考查宾语从句的用法，宾语从句要用陈述句语序，故排除C、D；因为use前有主语I，其后有宾语it，故不可用what引导，故选A。