---What caused the party to be postponed?--the invitations .A. Tom to delay sendingB. T

问题补充：

---What caused the party to be postponed?

----the invitations .

A. Tom to delay sending

B. Tom’s delaying sending

C. Tom delaying to send

D. Tom delayed to send

答案：

A. Tom to delay sending

(答案→)B. Tom’s delaying sending

C. Tom delaying to send

D. Tom delayed to send

解析：句意为：--啥事导致了派对往后延迟呢

---汤姆迟迟没有发送邀请函

由对话可知，what在疑问句中做主语的成分，答语是针对what而言，用替换法，从语法角度讲，在此题中替代what只能是名词或代词，据此可排除A,D； B,D均为动名词，值得注意的是tom是delay逻辑上的主语，故要用其物主格的形式，故选B