______ you have known everything about it, it is unnecessary for me to talk about it again.
| A．As soon as | B．Now that | C．Although | D．While |
We _________ the difficulty together, but why didn’t you tell me?
| A．should face | B．might face | C．must have faced | D．could have faced |
________ at the door before you enter my room, please.
| A．Knock | B．Knocking | C．Knocked | D．To knock |
________ with care, one tin will last for six weeks.
| A．Use | B．Using | C．Used | D．To use |
— Can I have a day off tomorrow, Mr. Johnson?
— ________. I can manage without you.
| A．Forget it. | B．I’m afraid not. | C．It depends. | D．Of course. |
—Why not have a birthday party for our mother?
—________.
| A．Good idea | B．That's all right | C．You are welcome | D．Never mind |