commercial用法he is appearing ______ for a sports productsat a commercial,还是on a commercial两个有何区别?（这个回答的话追加分～）

commercial用法he is appearing ______ for a sports productsat a commercial,还是on a commercial两个有何区别?（这个回答的话追加分～） commercial He sure is.中的sure用法是什么?He sure does. is he/does he/isn't he/doesn't he这些疑问语气的用法 He is always confusing wheat with leek .confusing用法? he is a boy属于be动词的那种用法 He is the strongest boy这样的用法对不对 he is 和 he has和he does.的用法,区别 代词用法he is as good as 还是he is as good as she? That is why some countries have whaled for commercial pruposes. My Chinese Commercial Code is的翻译是什么? This document is of commercial confidentialPlease keep it where 和that的用法We live in a consumer society ___there is an enormous demand for commercial products of all kinds.在where 和that中选一个答案是where 为什么不是that呢··求解答 What he said is important.这个句子里what he said 是什么用法? he is not the man that he was before中的that是什么用法 he talks like a scholar which he is not which的用法 he is worrying he is worried 差别和bore一样吗?he is boring 他很无聊he is bored 他感到无聊.是否与worry用法一样?he is worrying he is worried 以下英文用法是否地道,为什么? Teaching Assistant in the course of Commercial Law