3、din 2.Whatare;for;usedfor3.—__________wasthezipperinvented________?—It____________________byWhitcombJudson.4.—____________________itbecomepopular?—Around1917.答案:3.Who;by;wasinvented 4.Whendid【学以致用】①(2013·成都中考)—Doyouknowwhoinventedthetelephone?—No.Ionlyknowit______in1876.A.invented B.