1.under the sun
This is easily understood as "under the sun", but in fact, it is not, and the real meaning has nothing to do with the sun. It means "(emphasizing the great number of things) under the heavens, in the world, in the whole world", and the meaning of "in the end; in the end".
例句：we sat there for hours talking about everything under the sun
We sat there for hours, talking.
we talked about everything under the sun.
We talk about everything.
We talk about everything
we sat there for hours talking about everything under the sun
they had spent the previous night chatting about everything under the sun.
Last night, they said they had a night of conversation.
the fashion-conscious will go for anything under the sun!
Popular consciousness will be everywhere.
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.
Once the sea was shipwrecked as water.
The Great Dictionary of Chinese and English
where under the sun could i have put the purse?
Where exactly did I leave my wallet?
2. in the sun
So how should "under the sun" be expressed? The correct translation should be "in the sun".
例句：i like looking for my shadow in the sun.
I like to find my shadow in the sun.
Don't read in the sun.
we sat in the sun .
We sat in the sun.
In addition, "in the sun" also means "sunny place": 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) .
They have booked a holiday to a sunny place.
dena took them into the courtyard to sit in the sun
Denna took them to the yard to bask in the sun.