学 海 无 涯UNIT1CBAD FTFFF achievement literacy proficiency fallen blunty obsolete ineffective completely DAB BADCUNIT2FFTFT BACD BCAD UNIT3FTFF CACB BCAD DBADDUNIT4BBC TTFT CCB DDAB UNIT5FTFT BCADD CDD CBDCUNIT6DBBC TFTTF CCAD UNIT7BCDA FTTFT BCADB UNIT8TFTFF ADCB BDCD UNIT9FTTFF BDDA BBAC UNIT10CB TTFTF BABD BADD UNIT11BADC BDAC TFFTFF CBAB ACBD UNIT12FTTFT BDABA ACBA BCDC TEST1C CDAB C DA C DAD B ADC D DBB BABDBTEST2A CDAC C AC C BDA A BAB D CAC ADBDC1