In many European countries, one has to decide much earlier what one's career is going to be, and there

is less freedom in changing one's decision _____ one has chosen a particular path. [ ]

A. once

B. before

C. until

D. as

为什么要做跨境电商？（）

A.有利于传统外贸企业转型升级

B.缩短了对外贸易的中间环节

C.为小微企业提供了新的机会

D.促进产业结构升级

E.有利于中国制造应对全球贸易新格局