-----This returned Chinese scholar has become one of the top experts in this field.
-----Yes, I know him very well. He _____ in Africa with wild animals for eight years.
| A．is working | B．had worked | C．worked | D．has been working |
Certainly I posted your letter—I remember ______ it.
| A．posting | B．to post | C．to be posting | D．have posted |
Scarlett Johnasson developed ______ interest in acting at three and has made herself perhaps ______ finest actress of her generation.
| A．an; a | B．/; the | C．an; the | D．/; a |
After being discovered by Dutch explorers in 1606，the eastern half of Australiaby the British in 1770．
| A．was claimed | B．claimed | C．was claiming | D．has been claimed |
Women prefer to buy food which has already been preparedit reaches the market．
| A．after | B．for | C．before | D．until |
Scientific surveys conducted during the climbs that Mount Huandoy in Peru
6395 meters high.
| A．shown；is | B．showed；was | C．shows；was | D．showed；is |