Once ______ , the plan can’t be changed.
| A．begin | B．beginning | C．began | D．begun |
The astronauts found that ______ the spaceship went further and further into space, it became more and more difficult to control its own movements.
| A．if | B．till | C．as | D．while |
What he said suggested he ______ angry with us so I suggest you ______ an apology to him.
| A．should be; should make | B．should be; made |
| C．was; make | D．was; to make |
Have you ever been to Mount Huangshan, ___________is famous for its pine forests and "sea
of clouds"?
| A．what | B．where | C．that | D．which |
writing the article, Mrs. Curie even forgot her dinner.
| A．Absorbed in | B．Absorbing at | C．Having absorbed by | D．To absorb in |
While riding in the street, _____________.
| A．someone called me from behind | B．my bike broke down |
| C．I heard my name called | D．an old man knocked down |