After supper she would sit down by the fire，sometimes for ______ an hour，thinking of her young and happy days．
| A．as long as | B．as soon as | C．as much as | D．as many as |
The research lacksevidence，and therefore，its conclusions are doubtful.
| A．solid | B．fierce | C．severe | D．potential |
A good friend should be kind and helpful. _________ is my mother.
| A．A such friend | B．One such friend |
| C．Any such friend | D．Such one friend |
Though he is ill，he has not quit.
| A．smoke | B．to smoke | C．smoked | D．smoking |
Evidence of a powerful volcano, which erupted under the ice sheet of West Antarctica around 325BC and might still be active now, __________ so far by British scientists.
| A．confirmed | B．has confirmed |
| C．is confirmed | D．has been confirmed |
The reason why the girl decided to leave her boyfriend was that she didn’t feel _________.
| A．accurate | B．secure | C．unbearable | D．adequate |