His eyes suddenly widened. I knew a good idea must have _________ to him.
| A．happened | B．appeared | C．occurred | D．hit |
He tried his best to solve the problem, _______difficult it was.
A. however B. no matter
C. whateverD although
I'm moving to the countryside because the air there is much fresher than________ in the city.
| A．ones | B．one | C．that | D．those |
She said she was in great need of such a table and asked me how much _____ table would cost.
| A．such a beautiful wooden round | B．one such beautiful round wooden |
| C．one such round beautiful wooden | D．such a round beautiful wooden |
The two researchers originally set out to study the zebras in Africa and discovered a new species of tiger _______.
| A．by chance | B．in addition |
| C．by nature | D．in return |
The villagers are extremely thankful to him, without whose help the road to the village ________.
| A．can’t be built | B．couldn’t have been built |
| C．mustn’t be built | D．mustn’t have been built |