Learning another language is like stepping out of a door ,（ ） I can look back and see more clearly my own language .
A．by which
B．which
C．through which
D．on which
网友解答：C．through which
前面说了学习另外的一种语言就像是走出了一道门，
那么后面的句中是通过这扇门我可以回首和更清楚地看到我的母语。
我个人认为应该用介词through
不当之处，敬请见谅
网友解答：