________ modeling business is by no means easy to get into, the good model will always be in demand．

A.While

B.Since

C.As

D.If

答案及解析： A

解析：

解这道题，关键要搞清主从句的逻辑关系。从句modeling business is by no means easy to get into和主句the good model will always be in demand不是因果关系，也不是条件和结果的关系，而是表示表示让步。连词while可以引出让步状语从句。大意是：“尽管模特行业很难进入，但好模特总是供不应求。”