I don’t know the reason _______ you were absent from the meeting, and I am not sure whether someone will tell me the reason _______you haven’t told me.
All those second-hand goods are sold at ____ before.
——The switch to more low-carbon energy, I think, is _____. ——I agree with you.
Many a student ____ going to have themselves ____ in the hospital.
Three minutes earlier ____ we could have caught the early train to Philadelphia.
Many people have been ill from a strange disease these days, _____ we’ve never heard of before.