为什么说"What should I do"而不说"what I should do"

为什么说What should I do而不说what I should do It's time to decide what to do and ____A.when to do it B.when to doC.when I should do D.how should I do it【还要把为什么不能选这个答案的原因说一下.】 I asked him what ()A:should Ido B:to do it C:to do D:I should to do 和what to do 和how to do it 为什么 what to do 不加it 而how to do it 要加it 有人说选A也行 但是老师说选C为什么 i,d love to ,but what should i do i am not good at math.ireally do not donw ___ a.what should i do b.how should i doc.what to do d.how i should还有为什么选的原因 ( )67.I don't know_________I should choose.A.whyB.when C.which D.what .选c还是选D为什么 what should i do What should I do What should I do? what should i wear? what should I do? ------I don,t care what my teathers think -----Well,you ---------.A could B would C should D might选哪项,为什么? They always let me do______I think I should.A、whenB、thatC、howD、what答案为什么选D? What do you think I should tell Tom?可否说成Do you think what I should tell Tom? —What should I do,doctor?—__healthy ,you should take more exercise.A.Keep B.Keeping C.To keep D.Having kept选哪个?为什么? ——What should I do ,doctor ——____ healthy ,you should take more exercise.A.Keep B.Keeping C.To keep D.Having kept ,为什么? --- What should I do first?--- The instructions ______ that you should mix flour with water carefully first.A.go B.tell C.write D.say选什么 为什么 I asked my teacher ___.A.what courses should i take B.should i take what coursesC.i should take what courses D.what courses i should take 请选择,讲讲理由?