根据英语对话内容,完成对话中所缺单词,没空填一词.
A：Will you go home for Christmas this year ,Linda?
B：I want to go ,but I don 't know_______ I'll have enough money by then.
A：You live in San Francisco,don't you?
B：That's right .And the plane fare is very expensive.
A：Why don't you go by _________ It would be cheaper than the plane.
B：Yes,but I don't care for trains very much.
A：How about the bus That'not very _________,either.
B：I'm never comfortable on a bus ,and it _____such a long time .
A：Well,you can do one of two things ,then .Either start _________money for the plane fare ,or walking now .