what __ i do for you?a,can b,shall我选择了第一个,因为这是常用的交际语,但是我想知道第二个选项为什么不可以,标准答案也是第一个

Here is the man __ you've been looking for.可用whom Is there anything __ I can do for you.为什么不用what 而用that what can i do for you? what can i do for you? what can i do for you? What can I do for you? what can I do for you? what can I do for you?翻译.. What can i do for you? what can i do for you ,sir so,what can i do for you? what can i do for you? what should I do for you what can I do for you 回答 what can i do for you what can i Do not ask what I can do for you,Ask what you can do for me ! what can you __(do)?I can__(run).but i __(skate) now. 英语翻译what I do for you the other boys did for you ,but do you konw what I do for you I did not do for other girls. What do you do __ christmas?快