Investigations
A piece of cake
It's easy
Give me two meanings for... Bat
A baseball bat & the animal
Once in a blue moon
Not often, rarely
Give me two meanings for... Leaves
Trees have leaves or leave could mean to exit a room/place
Feeling under the weather
Sick or sad
Give me two meanings for.. Duck
The animal, or the action (ducking your head)
Let the cat out of the bag
Tell the secret
Give me two meanings for... Train
The type of transportation or it could mean practice ("athletes train to get better")
On cloud 9
Very happy
Give me two meanings for... Sink
A boat sinks under water, or the sink that we wash our hands in