“我们去吃冰淇淋吧。” “当然，为什么不呢？”

"Let's get some ice cream." "Sure, ___why ___not?"

当被邀请看电影时，我回答说：“为什么不呢？”然后就和她一起去了。

When invited to the movie, I replied, "___Why ___not?" and went with her.

“散个步怎么样？” “为什么不呢？天气很好。”

"How about a walk?" "___Why ___not? It's a lovely day."