It is generally believed that teaching is ___________it is a science.
| A．an art much as | B．much an art as | C．as an art much as | D．as much an art as |
The World Health Organization expects a vaccine(疫苗)against H1N1 to be by September or October this year.
| A．aggressive | B．available | C．absolute | D．abnormal |
Do swim with others. Otherwise, you .
| A．can get drowned | B．will get drowned | C．might have got drowned | D．might get drowned |
As is known to all, to smoking will do harm to your health.
| A．addicted | B．having addicted | C．being addicted | D．after being addicted |
the exploration of the botanical world on a large scale.
| A．It was not until the eighteenth and nineteenth centuries that; had begun |
| B．It was not until the eighteenth and nineteenth centuries when; began |
| C．Not until the eighteenth and nineteenth centuries did; begin |
| D．Until the eighteenth and nineteenth centuries; began |
How do you think that he was an hour late on such a short journey?
| A．it came about | B．did it come about | C．it was come about | D．was it come about |