1.under the sun
這個很容易被大家了解成“在太陽底下”,其實不然,真正意思跟太陽沒有半點關系。是指“(強調事物數量很大)天下,世上,全世界 ”,還有“究竟;到底 ”的意思。
例句:we sat there for hours talking about everything under the sun
我們在那兒坐了幾個小時,談天說地。
we talked about everything under the sun.
天南地北,我們無所不談。

天南地北,我們無所不談
we sat there for hours talking about everything under the sun
they had spent the previous night chatting about everything under the sun.
昨天晚上,她倆說東道西聊了一夜。
the fashion-conscious will go for anything under the sun!
流行意識将無所不在。
to a sophisticated person there is nothing new under the sun.; he who has sailed the
seven seas doesn't think much of mere rivers.
曾經滄海難為水。
《漢英大詞典》
where under the sun could i have put the purse?
我究竟把錢包放在哪兒了?
2. in the sun
那“在太陽下”應該怎麼表達呢?其正确翻譯應該是“in the sun”。
例句:i like looking for my shadow in the sun.
我喜歡在陽光下找自己的影子。
don’t read in the sun.不要在陽光下看書。
we sat in the sun .
我們坐在陽光下。
另外,“in the sun”還有“陽光充足的地方”的意思:in a place where it is warm and the sun shines a lot
they've booked a holiday in the sun (= in a place where it is warm and the sun shines a lot) .
他們已經預訂好了去陽光充足的地方度假。
dena took them into the courtyard to sit in the sun
德娜帶他們到院子裡曬太陽。