—Could you tell me _____?

—Certanily. In half an hour. [ ]

A. when will the high speed train arrive        

B. when the high speed train will arrive      

C. when would the high speed train arrive      

D. when the high speed train would arrive

在知识学习中，根据言语信息复杂程度通常把知识学习分为哪几种形式？