I know idiom
B1 （表示突然想到好主意、答案、解决办法）我有个主意，我知道了，我有办法了
said when you suddenly think of a good idea, an answer, or a solution
I know - let's go to the beach! 有了——我们去海滩！
B2 （表示赞同）是的，没错
said to show you agree with something someone has just said
"But he's so awful." "I know - he's dreadful." “但他很令人讨厌。”“没错——他是令人不快。”