the reason ____ i plan to go is _____ she will be disappointed if i dontA that;because B why;that C why;because 为什么选B不选A、C

the reason ____ i plan to go is _____ she will be disappointed if i dontA that;because B why;that C why;because 为什么选B不选A、C
the reason ____ i plan to go is _____ she will be disappointed if i dont
A that;because B why;that C why;because 为什么选B不选A、C

the reason ____ i plan to go is _____ she will be disappointed if i dontA that;because B why;that C why;because 为什么选B不选A、C
第一个why是用来引导定语从句,修饰先行词reason
第二个that是用来引导表语从句（跟在Be动词后的（或相当于Be动词功能的动词）从句叫表语从句）