1. Over the moon – (Extremely pleased or happy)

For example, Usually, I love to spend most of the time with my family and friends because whenever they stay around me, I always feel over the moon.

2. Once in a blue moon – (Happening very rarely)

I go to the supermarket once in a blue moon.

3. Piece of cake – (very easy)

I’ll have to work really hard for the theory part of the exam, but the practical part will be a piece of cake, because I’ve been practicing for so long.

or

Doing homework is not a piece of cake.

4. Under the weather – (unwell)

I did not perform well in exam, as I was feeling a bit under the weather.

5. Full of beans   -( A person who is lively, active and healthy)

I feel full of beans after a long sleep.