下列选项中，不属于FileReader类的方法的是（    ）

单项选择题This Certificate will remain in force until May 1,1989.________.A.This Sentence refers to the validity of the CertificateB.This Sentence refers to the time of the CertificateC.This Sentence refers to the date of the CertificateD.This Sentence refers to the issue of the Certificate

单项选择题在Excel中，为了不使其他人看到，提供的隐藏方法只能将行隐藏，而列不行。 A、正确 B、错误