你只能以不知情为借口了。

You'll just have to ___plead ignorance.

当被问及这个错误时，所有人都推说不知情。

When asked about the mistake, everyone ___pleaded ignorance.

他只能以工作压力大为由，为延迟提交辩解。

He could only ___plead pressure of work to excuse the late submission.