It took several hundred years ______ paper-making spread to western countries.
| A．when | B．before | C．after | D．since |
But for the help of my English teacher，I ________ the first prize in the English Writing Competition.
| A．would not win | B．would not have won |
| C．would win | D．would have won |
—It's the office！So you ________ know eating is not allowed here.
—Oh，sorry.
| A．must | B．will | C．may | D．need |
Keep up good state of mind even if you ________ fail plenty of times.
| A．must | B．will | C．can | D．should |
A left－luggage office is a place where bags ________ be left for a short time，especially at a railway station.
| A．should | B．can | C．must | D．will |
Oh，I'm not feeling well in the stomach.I ________ so much fried chicken just now.
| A．shouldn't eat | B．mustn't have eaten |
| C．shouldn't have eaten | D．mustn't eaten |