He bought a computer at a very low price为什么用at

he bought a computer several months ago高一英语He bought a computer several months ago.改写成：（）（）several months( )he bought a computer. He bought a computer yesterday.(改为否定句) he bought a computer yesterday.变否定句 He ________ the computer for half a year. A.has bought B.had bought C.has had D.had had He bought a computer at a very low price为什么用at He bought the cheapest computer. He bought the computer at the___ ____.改为同义句 He bought a pen. His school bought computer time for a year,but he used it up in a week.He was addicted. His school bought computer time for a year,but he used it up in a week.He was addicted.这是说比尔盖茨的一个文章. I bought a computer for a song.for a I bought him a notebook computer as a birthday present.he accept it ,------.说明理由 A.surprising and happily B.surprised and happy C.surprisedly说明理由 I helped Tom bought a new computer.改错 了 . 改写被动语态My parents have bought me a computer. My father bought a new computer yesterday改为被动语态 they have bought a computer 改成否定句 Jim bought a computer last Sunday对（last Sunday)提问 I bought a computer for ___.I often use it. I bought a computer for ___.I often use it.