在美国旅行的时候，我试着和不会说中文的朋友出去玩，这样我就只能说英语了。

While traveling in America, I'd try to hang out with friends who couldn't speak Chinese, so that I'd have no choice but to speak English.

youdao

他规定课上只能说英语。

He made it a rule only to speak English in class.

youdao

博克教授：我的情况是，家里有条规定，即我不会讲汉语，只能说英语。

Prof. Bork: In my case, there is a rule in the house that I can't speak Chinese, only English.

youdao