to abide by

to follow the law, rules or a decision: We’ll have to change our business model in order to abide by the new regulations.

to account for

to explain or justify: The warm weather accounted for the fall in sales of winter clothing.

to act up

to malfunction: My computer’s acting up today – I can’t access the internet.

to behave badly: Sorry I’m late – my 3-year-old was acting up and I couldn’t get him dressed.

to act upon

to take action as a result of something: We must act upon the evidence, despite our reservations.

to answer for

to be responsible for a problem: The old IT manager has a lot to answer for. No wonder he was fired!

to speak on behalf of someone: Due to my client’s absence, I will answer for him.

to ask around

to ask lots of people for information or help: I need to find a graphic designer. Could you ask around and see if anyone can recommend one?