I don't know ---- tomorrow.A.where shall we study B.where to

选 B
where to study = where I should study
考查宾语从句
A where shall we study （×）应该用陈述句语序
C how we should do （×）缺少宾语,应该加个 it
D how to do （×）缺少宾语,应该加个 it
再问： 何不选C？
再答： C 也是缺少宾语 how to do it what to do