---The vase cost me almost 100 yuan. ---Well, it was crazy of you to spend so much money _____you could buy a much cheaper one.
The organization is badly _________ of hands.
Do you remember the chicken farm _____ we visited three months ago?
I was about to go to bed _____ one of my old classmates made a call to me.
After Yang Liwei succeeded in circling the earth, Chinese astronauts __________ walk in space.
Students are encouraged to _________ the design competition for robots at the university.