Vitamin D helps our bodies make a special chemical,and this special chemical,________,affects our brains,making us feel happy.
We advised him __________________
He asked _____________ for the piano.
There are a great number of words in the English language ______________ on colors.A. based B. base C basing D. is based
--- Daddy, I don’t want to go to Jimmy’s birthday. --- You had better go. ____ you make a promise, you have to keep it.
Mary said they _____________________with each other for six years before they got married.