on computer 通过电脑
on the comupter 电脑的上面,比如电脑上面放着一个苹果
on paper （字,图形）在纸上
on the paper （一支笔,一副眼镜等实物）在纸上
in home 一般不这样说,一般会说in one's home或之间加其他形容词
at home 在家那in one's home和at home 有区别吗比如in one's home例句they're in my home.他们在我家at home 例句they're at home.他们在家懂了吧？嘿嘿