He would have been a doctor 20 years ago, but he _____ to be a teacher.
| A．chooses | B．chose | C．had chosen | D．has chosen |
28. Not until the train pulled into the next station ______________ her suitcase gone.
| A．Mary had found | B．had Mary found |
| C．did Mary find | D．Mary found |
27. Since 1994, the glacier in Antarctica has lowered by as much as 90cm, ______________sea level to rise.
| A．having caused | B．causing | C．caused | D．being caused |
26.—Flight MU257 _______________ . I must be off now.
—Have a nice trip.
| A．is being announced | B．has announced |
| C．was announcing | D．had been announced |
25. When _______________ comes to saving energy, big changes start with small steps, like turning off the lights.
| A．that | B．this | C．it | D．One |
24. Of the two cameras, I would prefer _______________ one, which is very easy for me to carry.
| A．a smaller | B．the smallest | C．a small | D．the smaller |