You have to keep alert when you are in the supermarket; otherwise, you might _____ what you actually don’t need at all.
Your composition is written very well ______________ some spelling mistakes.
________ makes mistakes must correct them.
We must take steps to prevent the __________ world population.
The amount of money that he saved reached _________ 30000 dollars.
It is pretty well understood_______controls the flow of carbon dioxide in and out of the atmosphere today.