He was busy writing a story, only ______ once in a while to smoke a cigarette.
| A．to stop | B．stopping | C．to have stopped | D．having stopped |
John complained to the bookseller that there were several pages _______ in the dictionary.
| A．missing | B．losing | C．dropping | D．leaking |
--- Who broke the window? --- I _____.
| A．had | B．broke | C．was | D．did |
It _____ them $300 a year to run a car.
| A．spends | B．costs | C．takes | D．pays |
Much _____ to be settled.
| A．remains | B．remembers | C．forgets | D．leaves |
It would be _____ a risk to let the child go to school by himself.
| A．running | B．following | C．passing | D．carrying |