---- It’s the office! So you _____ know eating is not allowed here.
---- Oh, sorry.
| A．must | B．will | C． may | D． need |
They decided to drive the cow away ______ it did more damage.
| A．unless | B．until | C．before | D．although |
No matter how frequently _______, the boy was always in low spirits.
| A．encouraged | B．encouraging |
| C．to be encouraged | D．was encouraged |
I don’t mind her criticizing me, but ______ is how she does it that annoys me.
| A．it | B．that | C．this | D．which |
—Why didn’t you come to Mike’s birthday party yesterday?
—Well, I _____, but I forgot it.
| A．should | B．must | C．should have | D．must have |
As usual, he put on a show as though his trip _____ a great success.
| A．had been | B．has been | C．were | D．was |