I regret _____ hard at school, or I would have succeeded in passing the exam.
| A．not to work | B．having not worked | C．to have not worked | D．not having worked |
Without a sure supply of water, farming in that area remains at the _______of the weather.
| A．disposal | B．risk | C．cost | D．mercy |
_______ the sun sinks lower, shadow spread ________ the courtyard.
| A．When; through | B．When; across | C．As; through | D．As; across |
—He was nearly drowned in a pool.
—Oh, when was ___ exactly?
— It was in 1983 ____ he was swimming with his friends.
| A．this; that | B．that; when | C．that; that | D．what; when |
— She joined a football team last fall and was recently made captain.
— Never _____ she'd ever have that much energy.
| A．I had thought | B．I would have thought |
| C．could I have thought | D．will I have thought |
Never before ____ such a smoke in the room.
| A．have I read | B．did I read | C．do I read | D．am I reading |