Here is a list of some common phrasal verbs with explanations and example sentences.

Act up

To act is to behave badly or to function improperly.

• Whenever we have guests, the children will start acting up.
• I think I need to get this laptop repaired because it has started acting up again.

If a part of your body acts up, it develops some problems or become painful.

• My head has started acting up again. I need to get it examined.

Act on

To act on something is to do something because you have been asked to do so.

• I am acting on the advice of my advocate. (= My advocate has asked me to follow a certain course of action.)
• You can’t blame them. They were merely acting on the instructions of their boss.

Act out

To act out is to express your feelings through your words or actions.

• She was acting out her feelings of insecurity by aggressively guarding her privacy.

Add up

To add up is to calculate the total of several numbers.

• I am not good at adding up in my head. I need a calculator for doing even small sums.
• You might ignore them by don’t forget that all these small expenses will soon add up.

If a set of facts does not add up, there is something wrong with it.

• You have been working with them for well over five years and you have earned them huge profits, but you haven’t received a raise in all these years. It just doesn’t add up.
• She must be lying. Her explanation just doesn’t add up. (= It doesn’t make sense.)

Ask out

To ask somebody out is to invite them on a date.

• If you have a huge crush on her, why don’t you ask her out on a date?

Ask over

To ask somebody over is to invite them to your home.

• We could ask them over for dinner.