used to show that you feel the same way as someone or agree with them

"I'll be so glad when this project is finished." "And how!" “这个项目完成了我会很高兴。”“我也是！”

"She's very keen on animals, isn't she?" "And how!"

"We really need a new photocopier." "And how."

"I'm fed up with him demanding to be waited on hand and foot." "And how!"

"Were you lonely while I was away?" "And how!"