Unit2RobotsBirthanddeathBornon2January，1920Diedon6April，1992inNewYorkBeforeworkingasawriterStartedworking1._inhisparents2._storeJoinedthe3._ofthePhiladelphiaNavyYardasa(n)4._chemistBecameabiochemistryteacheratBostonUniversitySchoolofMedicineAsawriterHis5._forwritingbecameobviousat11andhebegantotakehimselfseriouslyasa6._Beganhavingstories7._insciencefictionmagazinesin1939Publishedhisfirst8._in1950andhisfirstsciencebookin1953Receivedmany9._forhissciencefictionbooksandhissciencebooksInventedatheoreticalframeworkdesignedtoshowhowideasand10._maydevelopinthefuture类类型形式用法一般式tobedone发发生在谓语动谓语动作之后或与谓语动谓语动作同时发时发生完成式tohavebeendone发发生在谓语动谓语动作之前