________ at the door before you enter my room, please.
| A．Knock | B．Knocking | C．Knocked | D．To knock |
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.
| A．Once | B．Even if | C．Unless | D．In case |
Mary said they _____________________with each other for six years before they got married.
| A．has fallen in love | B．had fallen in love | C．had been in love | D．has been in love |
--- My sister is very upset today.
--- It is your fault. You ________________ the bad news to her yesterday.
| A．should tell | B．should have told |
| C．shouldn’t tell | D．shouldn’t have told |
Mother asked the youngest kid _____________ with his toy car.
| A．what the matter is | B．what is the matter |
| C．what the matter was | D．what was the matter |