The road is covered with snow. I can’t understand ________ they insist on going by motor-bike.
| A．why | B．whether | C．when | D．how |
We don’t have enough money .We,_______, can’t afford to buy the car.
| A．therefore | B．so | C．however | D．thus |
To enjoy the scenery, Irene would rather spend long hours on the train _____ travel by air.
| A．as | B．than | C．to | D．while |
Professor Smith, along with his assistants, _____on the Project day and night to meet the deadline.
| A．work | B．working | C．is working | D．are working |
He met his previous teacher ________ at abroad.
| A．by any chance | B．by the chance |
| C．by chance | D．by a chance |
Tom, ______ yourself .Did you forget the school rules?
| A．behave | B．believe | C．perform | D．conduct |