选择C.
完成时强调的是动作的结果对当时的影响.而过去时则描述以前所发生过的动作.
Is that Bob speaking?
答：Sorry he is not in he ___abroad on business
A.gose B.went
C.has gone D.was
是Bob吗?对不起,他不在,因商务上的事,他出国了.