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

--- 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→)A. when I can use itB. what I can use itC. why can I use itD. how can I use it解析：在复合句中用作宾语的从句叫宾语从句。　1．语序无论主句是陈述句还是疑问句，宾语从句都必须使用陈述语序，即“主句＋连词＋宾语从句（主语＋谓语＋……）”句式。 CD语序不正确，B项连接词错误。但是你能告诉我我能什么时间使用吗？故选A。

这下我知道了