Pleasewriteareport________theabovesubjectsaretobecovered.
B
in which the above subjects are to be covered 是 report 的定语从句。 which 指代先行词report ， in 用于与 report 搭配。
Whycouldn’tyou________ananswerwhenIaskedyouwhyyouwerelate?
Thehousewasquietinthenight,________theoccasionalcoughingfrommythroat.