Please write a report ________ the above subjects are to be covered.
B
inwhichtheabovesubjectsaretobecovered是report的定语从句。which指代先行词report，in用于与report搭配。
Asforfamilyeducation,parentsareencouragedtorelyon________ratherthanpunishment.
Chinaisamountainouscountry.Hills,mountains,andplateauscover_______ofthetotalarea.
______alittleearlier,Iwouldhavecaughtthetrain.