道理

There is some measure of truth in your remarks.

Development is of paramount importance.

Our major task is to build up the country.

He is explaining to the children why objects expand with heat and contract with cold.

Enumerate the facts and reason things out.

What he said made no sense to me.

be reasonable/logical; have reason for (sth/doing sth); there is reason in (sth)

be unreasonable; be against reason

be reasonable; listen to reason; be open to hear reason

We'll decide what to do after we gain a clear understanding of the situation.

I know what's to be done. / I have a way to solve the problem.