Dan has already given you a sense of the dramatic change that occurred between the '20s and the '30s.
Can I omit the second highlighted the in this sentence? I know there is a thing called ellipsis, that allows you instead of writing the A and the B
just write the A and B.
the [A and B]
or[the A] and [the B]
. Either way is fine.an [A or B]
can be also be expressed as[an A] or [a B]
.