Along with the letter was his promise he would visit me this coming Christmas.A. whichB.

问题补充：

Along with the letter was his promise he would visit me this coming Christmas.

A. which

B. that

C. what

D. whether

答案：

A. which

(答案→)B. that

C. what

D. whether

解析：that从句是对promise的解释、说明，不存在修饰作用，为同位语从句，故选B。如选A，应引导定语从句，起修饰作用。