【正文】
8. I think it is necessary for my 19yearold son to have his own mobile phone, for I sometimes need to make sure if he ______ home for dinner. A. e B. es C. has e D. will e 9. My friend, who ______ on the International Olympic Committee all his life, is retiring next month. A. served B. is serving C. had served D. has served 10. Ladies and gentlemen, please fasten your seat belts. The plane ______ . A. takes off B. is taking off C. has taken off D. took off 11. He ______ as a national hero for winning the first gold medal for his country in the Olympics. A. regarded B. was regarded C. has regarded D. had been regarded 12. Teenagers ______ their health because they play puter