B,C
You will find how great benefit {the computer (you own)can be } each time (when you use it to help you work).
you own 修饰the computer,简化句子时可略去.
each time 及其后面的是时间状语when 引导,是修饰的,简化时也可先不看.
此时就剩下you will find how great benefit the computer can be.翻译成你就会发现（你拥有的）电脑是多么有优势（每当你在工作中用它解决问题的时候）.