let nature take its course

answer the call of nature

To satisfy a bodily urge to urinate or defecate.

better nature

the more amiable qualities of someone

buy to let

To purchase a property as in investment, and to let it out for rental instead of living in it

crash course

A quick, intense course of learning, especially one which is informal or hurried.

cross to take up

Alternative form of cross to bear.

don't let the door hit you on the way out

Used as a command to leave in haste, or to indicate that one is glad, or at least unmoved, to see the addressed person leaving.

due course

Regular or appropriate passage or occurrence

forget to take one's medication this morning

To be annoyed or irritable, or to behave in an ill-mannered way, particularly in the morning.