i have been skating since nine years

i have been skating since nine years 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 have been skating _____ nine oclock.A.for B.since C.at D.from I have been skating for 3 years.=I have _____ _____ I came here.急.I have been skating for 3 years.= I _____ to _____ _____ _____ ago. i have been skating() nine o'clock A for Bsince C at D fromWHY ,GIVE ME SOME REASONS 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 how long have you been skating?怎么回答 -I saw Jim and your brother in the park yesterday morning.-they ---- skating there,right?A.practiced B.were practicing C.have practiced D.have been practicing They have been skating for five hours 同义句 They have been skating_______ _____ ________ ______ 2 the earthquake is a ____( 自然 )disaster 3 i have been skating s_____ iwas seven years old 4 i'm 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 didi you skate today?How long did you skate today?How long have you been skating today?Was this your first skating marathon?Do you skate every day?When did you get your first pair of skates?How long have you been skating?No, I skated in a ma 【急!】have been skating与have ever received怎么区别 在线等.have been skating与have ever received怎么区别? -How long did you skate?-I skated for two hours.第一句中”did”” skate”能换成”have””been skating”?为什么? how long have you been skating?这句里有的been,是属于什么句型.有点忘了. I have been selling I have been trying I have ever been