Don't worry We are thinking about_____A if we should do B that we should doB这种说法为什么不对顺便说下宾语从句引导词（w疑问词 if that）的相关知识
问题描述：
Don't worry We are thinking about_____
A if we should do B that we should do
B这种说法为什么不对
顺便说下宾语从句引导词（w疑问词 if that）的相关知识
答
B选项改成what to do 就对了.这句话从句缺do 的宾语、what 是关系代词、而that 只做引导词不充当任何成分