In some cases，different approaches ________ the same scientific problem lead to conflicting theories.
| A．to | B．in | C．of | D．for |
28. The farm as well as its neighboring hills we once spent so much time ____ on a new look as recently as last year.
| A．on having taken | B．has taken | C．on has taken | D．having taken |
27. _____ some of the juice — perhaps you'll like it.
| A．Trying | B．Have tried | C．To try | D．Try |
26. It was said that _____ was the reason why he didn't attend the meeting.
| A．why | B．why that | C．that which | D．That |
25. –––– How did you feel when Linda won the gold medal in the 29th Beijing Olympic Games?
–––– I couldn’t be _______.
| A．more exciting | B．more excited | C．most exciting | D．most excited |
24. Let’s learn to use the problem we are facing________a stepping-stone to future success.
| A．to | B．for | C．as | D．By |