“Cut someone some slack”

“Catch your breath”

To rest until you can breathe normally again.

“Dig your heels in”

To refuse to change your opinion or position.

“Cool as a cucumber”

Very calm, especially under pressure.

“Catch someone off guard”

To surprise someone unexpectedly.

“Come clean”

To tell the truth about something.

“Change your tune”

To change your opinion or attitude.

“Cry wolf”

To ask for help when there is no real danger, so people stop believing you.

“Crash course”

A short and intensive course.