In face of _____failure, it is the most important to keep up _____ good state of mind.
| A．/; a | B．a;/ | C． the; / | D．/ ;the |
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 |
My sister，an inexperienced rider，was found sitting on the bicycle _________ to balance it．
| A．having tried | B．trying |
| C．to try | D．tried |
_________ in the fields on a March afternoon，he could feel the warmth of spring．
| A．To walk | B．Walking |
| C．Walked | D．Having walked |
_________ to reach them on the phone，we sent an email instead．
| A．Fail | B．Failed |
| C．To fail | D．Having failed |
We went right round to the west coast by __________ sea instead of driving across _________ continent. 
| A．the … the | B．/ … the | C．the … / | D．/ … / |