1.Sincethen,Ihavebeenreadingbooksquiteoften.

　　2.Eversincethen,Ihavebeenreadingbooksquiteoften.

　　3.Fromthenon,Ioftenread(发音为red)books/Ihavebeenreadingbooksquiteoften.

　　（1）和（2）用现在完成进行时（因为强调从那时候一直到现在为止）,（3）可以用一般过去时（和现在没有直接的联系）或现在完成进行时.

　　用哪一句话,关键是要看“从那时起”在英文中的用法.请参考《结束蹦单词时代：外教教你用连词》,中国书籍出版社,第135-136页：

　　1.IheardthissongwhenIwaslittle.Sincethen,Ihavealwayslikedlisteningtoit.

　　2.Igotanewjoblastmonth.Mycareersincethenhasbeengoingverywell.

　　3.Iboughtanewcaraweekago,andsincethenIhavebeendrivingtowork.

　　4.IcaughtacoldrecentlyandsoItooksomemedicine,butsincethenmycoldseemstohavebeengettingworse.

　　5.Peopleusedtogetmarriedatayoungage,buttimeshavechangedsincethen.

　　6.IstartedlearningEuropeanlanguageswhenIwasatprimaryschool.Eversincethen,languagehasbeeninexplicablywovenintomylife.

　　7.Myfriendgavemeagoodluckcharm,andeversincethenIhavehadnothingbutgoodluck.

　　8.Aguytoldmethathelikedme,buteversincethenhehasn'tcontactedme.

　　9.Igotathroatinfectiontwodaysago,andhavebeenonantibioticseversincethen.

　　10.Inearlydrownedintheseawhenourboatsank.Fromthenon,Ilearnthowtoswim.

　　11.Hequitsmokingfiveyearsago,andfromthenonhehasbeenfeelingmuchhealthier.

　　12.Ididn'tgetthegradeIwantedinmylastexam,butfromthenonIworkedextrahard.

　　13.Hewasreleasedfromprisonnotlongago,andhaslivedanhonestlifefromthenon.

　　以上连词都表示“从那时起”或“从那以后”,但sincethen强调从那个时间点开始或从那个时间点以后到现在为止.eversincethen强调从那时候开始一直到现在或从那时以后一直到现在的时间段.fromthenon强调从某一过去的事情开始或从某一过去的事情以后,和过去的联系比较强.sincethen可以放在第二句的开头（后面放逗号）、主语后面、and/but后面,其后放从句,或句尾.eversincethen、fromthenon和sincethen的用法一样,只是不能放在主语后面.sincethen、eversincethen和现在完成时或现在完成进行时连用.fromthenon和一般过去时、现在完成时或现在完成进行时连用.这些连词既是口语又是书面语.