Not until the early years of the 19th century ________ what heat was.
| A．man did know | B．did man knew |
| C．didn't man know | D．did man know |
Chinese netizens （网民） doubt ______they called Western freedom of speech , seeing the dishonest reports about the recent riots（暴乱） in Tibet by some Western media．
| A．that | B．which | C．what | D．Whether |
Research _____________ that men find it easier to give up smoking than women．
You _____ be 18 years old before you are allowed to drive a car ,and it’s also essential to get a driver’s license
| A．could | B．may | C．can | D．have to |
To be qualified for the job , _________
| A．ir is required that one has profound knowledge |
| B．profound knowledge is important |
| C．profound knowledge is a must |
| D．one needs to have profound knowledge |
I gave his book to read, but after a page or two he would put _______book down and pick up _________new one．
| A．a; the | B．the; 不填 | C．the; a | D．a; a |