They knew they had done something terribly wrong and lied to cover it up.

他们知道已犯下了大错，并撒谎来掩盖这一错误。

《柯林斯英汉双解大词典》

I was very worried about the competition result, but I could only cover it up by joking.

我非常担心比赛结果，但我只能通过说笑话来掩饰不安。

youdao

If you try to cover it up, they may be fooled at first, but eventually they catch on.

如果你试图掩饰这些，刚开始他们可能被糊弄住，但是他们最后终将发现真相。

youdao

However,Republicans and Democratic opponents said the resolution itself was biased, asserting that by passing it the House would be demonstrating it wants to cover up the truth about actions in Gaza by both Hamas and Israel.

VOA: standard.2009.11.04

Moving a stack of size 3, again, if I want to go over there, I need to make sure I can put the spare one over here before I move the bottom one, I can't cover up any of the smaller ones with the larger one, but I can get it there.

移动上面的三个圆盘的话，我在移动最底下的圆盘之前，同样要确保剩下的,是在另外一个柱子上，因为我不能把大的圆盘,放在小的上面。

麻省理工公开课 - 计算机科学及编程导论课程节选

They often know about their failures and they just try and cover it up each time.

BBC: News

He knew how to cover it up, that's why his work was worth so much.

NPR: 'Arson' by Nick Lysohir

He got into an illicit affair, and he tried like everybody else to cover it up.

CNN: Sen. Ernest Hollings' closed-door impeachment statement