Putting out forest fire is regarded as one of _____ problems in the world．（ ）
| A． |
difficult |
B． |
more difficult |
| C． |
most difficult |
D． |
the most difficult |
The club members said it was one of the best compositions they____.
| A．hear | B．have heard |
| C．heard | D．had heard |
It was said that Lebron James _____the Most Valuable Player of the 2013 NBA finals.
| A．has been named | B．would name |
| C．had been named | D．Named |
By the time he was ten, Edison _________ experiments in chemistry.
| A．had already done | B．already had done |
| C．was already doing | D．already did |
It was the first time in my life that I _________ the Great Wall. You can’t imagine how excited I felt!
| A．had visited | B．visited |
| C．visit | D．have visited |
By the end of Last year, we _____ more than 1,100,000 cars.
| A．were producing | B．produced |
| C．had produced | D．would produce |