Not giving up when meeting with difficulties is a good quality, ______ you can benefit from.
| A．what | B．that | C．one | D．the one |
_________ in the fields on a March afternoon，he could feel the warmth of spring．
| A．To walk | B．Walking |
| C．Walked | D．Having walked |
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 |
_________ the project as planned，we’ll have to work two more hours a day．
| A．Completing | B．Complete |
| C．Completed | D．To complete |
. We finished the run in less than half the time _________．
| A．allowing | B．to allow |
| C．allowed | D．allows |