The reason I’m writing to you is to tell you about a party on Saturday.A. becauseB. whyC.

问题补充：

The reason I’m writing to you is to tell you about a party on Saturday.

A. because

B. why

C. how

D. which

答案：

A. because

(答案→)B. why

C. how

D. which

解析：本题考查定语从句。先行词为the reason在定语从句I’m writing to you中作原因状语，故用why，选B。