问题补充：
Now the question that you must carefully consider is can be put into practice.
A. how what you have learned
B. how you have learned
C. that why you have learned
D. how that you have learned
答案：
(答案→)A. how what you have learned
B. how you have learned
C. that why you have learned
D. how that you have learned
解析： 考查表语从句，表语从句中又含有一个由what引导的主语从句，句意：现在你必须认真考虑的问题就是你如何把你所学的东西应用到实践中。所以选A。
