几道八年级英语题目。找出错误并改正:1.JackhasstudiedChineseforSeptember.2.Mymotherhasworkedtheresincetwoyears.3.Ihaveboughtanewschoolbagtwomonthsago.4.Wherehaveyougone?5.Howlongdidyouknowher?用for或since改写句子:1.IlearnedEnglishtwoyearsago.2.Thestudentscametoourschoolin2006.3.Mikeboughtavideomachinein1999.4.Shebacameourheadteacherayearago.