— Now I must go I shall be late for the train.— Have a good trip. Goodbye.A. orB. soC. an

问题补充：

— Now I must go I shall be late for the train.

— Have a good trip. Goodbye.

A. or

B. so

C. and

D. but

答案：

(答案→)A. or

B. so

C. and

D. but

解析：or或者，否则；so因此；and 和，并且；but但是。句意：现在我必须走了，否则我上火车要迟到了。——祝你旅途愉快。结合语境可知选Ａ。