They _________ the habit of visiting old friends,_________ I think is great.
| A．keep on;which | B．keep up;which |
| C．keep on;as | D．keep up;as |
The Golden Gate Bridge, _______ several hundred years ago, is worldwide famous.
| A．which is built | B．built |
| C．having built | D．which built |
Paper produced every year is ______the world’s production of vehicles.
| A．the three weight of |
| B．three times as heavier as |
| C．three times the weight of |
| D．as three times as heavy as |
We had a long way to go, and the snowstorm ________ our difficulties.
| A．referred to | B．added to |
| C．belonged to | D．turned to |
--May I open the window? It’s too hot.
--_____________.
| A．It’s your turn. | B．You have got it. |
| C．Go ahead. | D．Hold on. |
John began to study French last Sunday. ____________
| A．His brother did so. | B．So did his brother. |
| C．So his brother did. | D．His brother so did. |