在不知道怎么做或怎么说的时候就沉默吧 的英文

To be silent when you dont know how to do it or what to say

Be silient when you how to do it or how to say it

When you don't know how to deal with it, keep silent.

when I don't know what to do or what to say,I choose keeping silent 一定要是what to do 不能用how的

keep silent when you do not know how to do it or what to say

Just keep silent when you don't know what to do or what to say.