With the help of high technology, more and more new substances ______ in the past years.
| A．discovered | B．have discovered |
| C．had been discovered | D．have been discovered |
——Did you know any Chinese before you arrived in Beijing?
——Never ________it, actually.
| A．had I learned | B．have I learned | C．I have learned | D．I had learned |
He was disappointed to find his suggestions ________.
| A．been turned down | B．turned down | C．to be turned down | D．to turn down |
He is recovering now. is no need to call in a doctor.
| A．It | B．There | C．This | D．That |
Everything will be all right. We must never stop taking a(n) ________ attitude towards life.
| A．understanding | B．opposite | C．relaxed | D．optimistic |
There’s not much exciting news in today’s paper,_____?
| A．isn’t it | B．are there | C．is there | D．aren’t there |