The main job of the lungs is to exchange oxygen in the air we breathe in for carbon dioxide, which we breathe out.
(The main job of the lungs; is; to exchange oxygen in the air) (the air; breathe; L:in) (carbon dioxide; breathe out; we)
The main job of the lungs the air carbon dioxide
is breathe breathe out
to exchange oxygen in the air
L:in
we