1. Our Acting Manager had to put off his trip,
because there was no vacant seat on the plane.
(we use the preposition on, is it correct or not? --
Yes)
2. Lots of farmers work on the farms.
(we
use the preposition on, is it correct or not?--
Yes. And in this sentence, do
we use the definite article before the word farm or not?--
if you are speaking of specific farms in the context, use the;
if you are speaking generally, don't use the)