he skated for four hours 为什么加for

he skated for four hours 为什么加for San skated for four hours 对划线部分提问 He's been studying there for （two whole hours）?对括号提问I missed the train （an hour ago） （ 同上）He skated from 7:00 to 9：00 yesterday （同上）He has been skating for four hours （否定句）He ___ ____ ____ for four hours I skated for four hours与I have been skating for four hours的区别最好详细点,说的明白点 How long did you sleep last night?什么意识还有When did you start class today?how long have you been in class today?How long has Alison been skating?she's been skating for five hours.How long did Sam skate?He skated for four hours.是什么意 How long has alison been skating?How long has alison been skating?She's been skating for five hours.How long did sam skate?he skated for four hours.我要解释的是那四句 因为本人英语差 所以请你们告诉哈我 回答了还有加分 my brother skated for the w___two hours yesterdayRT. I skated but I fell down for many (1)He started skated skating four years ago.He ___ ___ ___for four years .(2)I will have a picnic tomorrow.He said that he___ ___ a picnic the next day.(3)Why don't you give him a gift?You___ ___ him a gift.(4)You'd better not cut in line when others he`s been skating for four hours 改为否定句 By 11 o’clock,he will ____ for four hours. he has been to China four times还是for four times He practices the piano for four hours every day.划线提问for four hours 是划线部分 how long did you skate?--I skated for two years.请帮忙分析一下此句话的语法I skated for two years.I have skated for five years两句有什么区分 he is p____ enough to wait for me for about four hours. He （h ）six classes every day,four in the morning,two in the afternoon. Jim skated _______a marathon last year.A.at B.in C,on D.for for一four