请问"I _ been learning English for four years."中,（ ）应选哪个?A.have B.am C.were

请问I _ been learning English for four years.中,（ ）应选哪个?A.have B.am C.were 请问i've been down I _ all the housework at home,but recently I have been too busy to do it.A.do B.did请问为什么? I have been collecting shells for three tear and a half同义句转换I have been collecting shells for _ _ _ _. 请问 I have been underemployed 怎么翻译 I have been playing the piano since I _(be) 6 years old.填was,been,还是其他的什么? I felt most angry about the way _ I have been treated. 请问“>_ 请问jack has been busy _ his report.这句话中应该填什么 I have never been to _ amusement Park.A.a B.aI have never been to _ amusement Park.A.a B.an.C./D.the I have never been to beijing(_) A.too B.either C.neither D.also Mr Green left Shanghai two days ago =Mr Green _ _ _ _Shanghai since two days ago中间那个空是has been away from ,请问为啥, Where _ you I went to see the football match.A have ;been B have ;gone C have;been to D have;been in i am been losing sleep 请问这是什么时态 请问“I shouldn't have been here.”怎么翻译? $_$(txtValidate)[i].style.display = ;请问：这里的 $_$ 是什么意思 ?整个语句是什么意思?谢谢 请问怎样填请问怎样填 All the work _ (do)they felt satisfied.has been done但是给出的答案是having been done为什么呢？ I have been like this since last month 句意? 且请问been充当什么成分