contract in (to)
Since it started, many companies have contracted in to lend their support.
contract * out +
They have contracted out their catering services to save money.
The firm contracts out most of the basic building work.
contract out of +
I contracted out of the deal years ago.
cool * down +
(使) 冷卻；(使) 變涼
I left the tea for a minute until it cooled down enough to drink.
It took me ages to cool down after the argument.
We’ll talk to Harry once he cools off and can talk rationally.
coop * up +
They cooped the dog up in a tiny room.
He was cooped up in a tiny room.
They really copped it when they got caught shoplifting.
We copped off early on Friday because there was nothing to do.
She copped off with Damian at the end-of-term party.
She was going to take a Master's degree but copped out and chose the Diploma course instead.
He has copped out of his responsibilities.
cotton on (to)
It took me ages to cotton on to what they were planning.
It took him a while to cotton on to what I was saying.