The fifth generation computers, with artificial intelligence, _____ and perfected now.
| A．developed | B．have developed |
| C．are being developed | D．will have been developed |
It suddenly occurred to me I hadn’t locked my door．
| A．which | B．where | C．that | D．whether |
The result was not the same as they had expected, ______ was rather disappointing.
| A．that | B．which | C．when | D．what |
London's road traffic map is like a cobweb(蜘蛛网) of small streets, offering drivers more _______ when one road is blocked.
| A．barriers | B．characters | C．similarities | D．alternatives |
We need some more facts and figures ______ we make the final decision.
| A．since | B．before | C．after | D．until |
Not until he went through real hardship _____ the love we have for our families is important.
| A．had he realized | B．did he realize | C．he realized | D．he had realized |