I skated for four hours与I have been skating for four hours的区

I skated for four hours与I have been skating for four hours的区 I skated for 4 hours . I have been skating for 4 hours. I ha i've been skating for five hours=i skated for five hours Sam has been skating for four hours.改为否定句 he`s been skating for four hours 改为否定句 he skated for four hours 为什么加for San skated for four hours 对划线部分提问 Next is Sam ,and he has been skating for four hours 现在完成时态的 I've been skating for five hours 这句是什么时态,与I've skate i need to have a rest.we ___(walk)non-stop for four hours -How long did you skate?-I skated for two hours. 翻译we have been on duty for four hours and now comes your tur