来自沈轶的问题
【Thebookhashelpedmegreatlyinmydailycommunication，especiallyatwork________agoodimpressionisamust．（）A.whereB.whenC.asD.which】
The book has helped me greatly in my daily communication，especially at work ________ a good impression is a must．（）
A.where
B.when
C.as
D.which
