帮忙看看这句I saw him at work,为什么要用at,不能用to吗

went to him at work i saw him ___hurry at the moment. when we got there ,we saw him ___ at the table .A work B to I was surprised to look at him.（同义句转换) I look at him in surp I was surprised to look at him.改同义句 I looked at him ____ ___ I saw Boys at the cinema 为什么用both the 而不 i saw him (get)on the bus just now.为什么不能用getting. Then I go to work at 8:15.同义句 I saw him reading a newspaper at eight this morning I saw him work in the garden yesterday.中WORK为什么不+ED·要是+了呢? Jim ()be at home at the moment,because I saw him shopping at to tell you the true ,i don't like him at all 开头为什么用 to