Insert the correct missing number from the choices given

Slap on the Wrist

There was no room to swing a cat in the party.

Do a roaring trade

Fill in the blank given below using the correct idiom.

When two heavyweights have an argument, its best to  sit on the fence  and not make either of the turn against you. 

Select the most appropriate meaning of the given Idiom.

WET BEHIND THE EARS

To pick holes

"The progress on the project was made  by fits and starts,  which caused delays in its completion."