——Did Tom come back late last night?——No. It was not yet 8 o’clock ____ he arrived home.
There are ______ in this building , I live on ______.
The water behind the Three Gorges Dams (三峡大坝) should be ______ higher than downstream(下游)。
There are _______ days in a year.
---How many teachers are there in your school? --- __________. , but I'm not sure.
There are _________ doctors and nurses working hard in that hospital.