No scientists can exactly figure out what ________ happened ________ at that time, which caused the extinction of the dinosaurs.
| A．on earth; on the earth |
| B．on the earth; on earth |
| C．on earth; on earth |
| D．on the earth; on the earth |
-- What can I offer you? Coffee, tea, orange juice, iced water …? -- _____________.
| A．Yes, please. Thank you. | B．I don’t care. Whatever. |
| C．Go ahead. None of my business. | D．Don’t worry. Too much trouble |
The cost of living in Glasgow is among the lowest in Britain, ________ the quality of life is probably one of the highest.
| A．since | B．when | C．as | D．while |
The sound of the birds __________happy memories of my childhood holidays.
| A．called up | B．called for | C．called on | D．called in |
In the USA, _______ Thanksgiving Day is a harvest festival．Traditionally, it is _______ time to give thanks for the harvest and express gratitude in general．
| A．the; a | B．/; the | C．/; a | D．the; the |
Measures have been taken to solve the problem, but it may be some time ____ the situation improves．
| A．since | B．when | C．unless | D．before |