The professor could hardly find sufficient grounds _____his arguments in favor of the new theory.
| A．to be based on | B．to base on |
| C．which to base on | D．on which to base |
--How long __each other before they ____ married?—For about a year.
| A．have they known; get | B．did they know; were going to get |
| C．do they know; are going to get | D．had they known;got |
--Is ___ here? –No, Bob and Tim have asked for leave.
| A．anybody | B．everybody | C．somebody | D．nobody |
In some parts of the world, tea __ with milk and sugar.
| A．is serving | B．is served | C．serves | D．served |
If you keep on, you’ll succeed___.
| A．in time | B．at one time | C．at the same time | D．on time |
Charles Babbage is generally considered __ the first computer.
| A．to have invented | B．inventing | C．to invent | D．having invented |