i 've been skating for five hours 为什么要用ing形式啊

八年级下册英语书语法：How long have you been skating?I've been skating since nine o'clock. i 've been skating for five hours 为什么要用ing形式啊 这道英语题它的考点是什么. I’ve been ________for five hours. A. skate B. skating C. skated 1.i think i'll ride my bike.2.if you do ,you'll be late.3.i think i'm going to stay at home.4.if you do,you'll be sorry.5.how long have you been skating.6.i've been skating for five hours.7.i've been skating since nine o'clock.8.how long did you skat 关于八年级英语的一个问题.i‘ve been skating for five hours.和.she’s been skating for five fourshave been doing sth是现在进行完成时,那she’s been skating for five fours.为什么是be been skating 这是人教版新目标八 I've been expecting I've been cryin Ive been to I've been filming. i have been skating since nine years A--So you've___skating for B--- I've been skating for five hours.括号里应该填什么单词才合适啊 I've been to me I've been waiting for i've been referred to I've Been Waiting 歌词 I'Ve Been Here 歌词 i've been ...是什么时态? I’ve been to the