[英文]
1. make a mountain out of a molehill
2. down-to-earth
3. on earth
4. done and dusted

1. 大驚小怪，小題大作//同"make a tempest in a teacup"
Instead of making a mountain out of a molehill, I think the best way to take action is just letting nature take its course.

2. 形容詞：腳踏實地
He is so warm and very down to earth, no wonder he is so popular with old and young.

3. 究竟、到底
What on earth is he doing right now???
What on earth is it?
(強調語氣，比what the hell好點w)

4. 大功告成(工作後連打掃都做了)
I have been snowed under the project for three months, but it's finally done and dusted now.

(然後今天推特回文的時態錯了QQQQ，是I had never been...before I met you...)