Answer:

Rate- it is expressed in percent and always has "%" sign.

Base- it represents a whole; the number from which a percentage is taken. It is formed after the word "of"

Percentage - it is a number taken from the base.

-hint word "is"

So basically to identify the rate base and percentage, we have these clue words.

Rate- always has a % sign.

Base- formed after the word "of"

And the percentage's hint word is "is".

Hope it helps goodluck!