—We can use QQ to talk with each other on the Internet.—Really? But can you tell me it.A.

问题补充：

—We can use QQ to talk with each other on the Internet.

—Really? But can you tell me it.

A. how I can use

B. how can I use

C. why can I use

D. when I can use

答案：

(答案→)A. how I can use

B. how can I use

C. why can I use

D. when I can use

解析：英语宾语从句中一般为陈述语序。How引导宾语从句表示方式方法，做状语。Why表示原因，when表示时间。句意：我们可以用QQ在网上相互交谈。——真的吗？但是你能告诉我怎么用。结合语境可知选A。