After days of discussion, his plan to be the best one.
| A．was to prove |
| B．proved |
| C．was proved |
| D．was proving |
Yoube Carol. You haven't changed a bit after all these years.
| A． | must | B． | can | C． | will | D． | shall |
Like ancient sailors, birds can find their way____ the sun and the stars.
| A．used | B．having used | C．using | D．use |
Last year was the warmest year on record, with global temperature 0.68 ℃the average.
| A． | below | B． | on | C． | at | D． | above |
Bach died in 1750, but it was not until the early 19th century____ his musical gift was fully recognized.
| A．while | B．though | C．that | D．after |
We must find out ____ Karl is coming, so we can book a room for him.
| A．when | B．how | C．where | D．why |