________, the boy couldn't enter his house.
| A．Since the key has lost | B．The key been lost |
| C．Lost the key | D．Having lost the key |
The two runners are neck and neck; _______ of them could win the race.
| A．either | B．neither | C．all | D．none |
I usually have ________ hamburger while waiting for ________7: 00 school bus.
| A．the; a | B．不填; the | C．a; the | D．不填; a |
My calculations werebasedonthe __________ thathouse prices would remain steady.
| A．theory | B．assumption | C．procedure | D．regulation |
Icamehomeverylatelastnight,__________,earlythismorning.
| A．atleast | B．onthewhole | C．inaword | D．orrather |
The black people thus lay onthehardwoodenboards,_________standup.
| A．unableto | B．couldn’t | C．wasunableto | D．can’t |