In some cases，different approaches ________ the same scientific problem lead to conflicting theories.
| A．to | B．in | C．of | D．for |
The little girl________the bus as soon as it stopped，but to her disappointment，there were no seats left.
| A．got on | B．got out of |
| C．got off | D．got to |
He________his leg when he________in a football match against another school.
| A．broke；played | B．has broken；was playing |
| C．broke；was playing | D．broke；had played |
From the dates________on the gold coin，it is confirmed that it was made five hundred years ago.
| A．marking | B．to be marked |
| C．marked | D．having been marked |
Linda worked for the Minnesota Manufacturing and Mining company，________as 3M.
| A．knowing | B．known | C．being known | D．to be known |
—We all had a lot of fun at the barbecue yesterday. Pity you weren't there.
—I really should have gone with you but I________on some remaining problems.
| A．worked | B．was working |
| C．would work | D．would have worked |