I can't tell you how happy I am.

我无法向你表达我多么高兴。

《牛津词典》

I heard it on my happiest evening; but I did not then know how happy I was.

这是我在最幸福的一个晚上听到的。但那时我并不知道自己有多幸福。

youdao

Can you imagine how happy your beloved one will be when you give him/her your DIY desserts on the special days like birthday, Mother's Day and Father's Day?

你能想象在生日、母亲节、父亲节等特殊的日子里给你的爱人亲手制作甜点，他们会有多开心吗？

youdao

"I doubt if you can understand how happy this modernizing has made me.

VOA: special.2009.12.07

And he asked them, "How happy are you going to be, ?" if you get the tenure?"

他问他们“你会多快乐，如果你得到终身职位“

哈佛公开课 - 幸福课课程节选

" And-- "How happy are you going to stay for?"

你会快乐多久“

哈佛公开课 - 幸福课课程节选

Let me begin by saying how happy I am to be back in the beautiful city of Prague.

WHITEHOUSE: Signing of New START Nuclear Arms Treaty with Russia

"I just think of everything I do and how happy it will make me to do it, " she says.

NPR: British Invasion: Laura Marling's Fearless Folk

Madonna had just finished thanking Michigan, her home state, and telling them how happy she was to be home.

FORBES: Madonna Shows Hometown Some Love, Detroit Boos and Shows Her Dis-R.E.S.P.E.C.T.