你只能以无知为借口。

You'll just have to ___plead ignorance.

当其他人对所给主题都声称无知时，独自处理问题并不好玩。

It is no fun being left alone to tackle a hitch when everybody else ___pleads ignorance to the given subject.

他以头痛为借口避开会议。

He ___pleaded a headache to avoid the meeting.