帮解决一下几道英语选择题,并详细说明理由,非常感谢!

帮解决一下几道英语选择题,并详细说明理由,非常感谢!
1,__Do you have your ticket,sir?
Yes,I have ___right here,in my picket.
A.a very one, B. this, C. one D, it
2. He would think to go there quicker than to come back,but it was just ____. A, another way, B. the other way, C.other way, D.the another way.
3.I wish I could offer you some cakes but there's ___left.
A, nothing,B, none one, C, none
4. Regulations require___need special diets___the cooking manager in advance. A.who, informs, B. whom, informal, C. whomever, inform, D. whoever, inform
5. Unstanding the cultural habits of another nation,especially___containing as many substances as the United States is very difficult.
A. one, B.the one, C, that , D, such
请解释一下好吗