23. —You started all the trouble. —But I didn’t to.
--How was your weekend, Rose?--Awful! This was the first time I ________ alone at home, bored to death.
Many citizens urged their government to take measures to _______ their carbon emission to reduce greenhouse effects.
Obama made _______ history by being elected as ________ first black president of the US.
--I think our school’s selective courses are of great use and I have learnt a lot from them.--Yes _______.
I was born in New Orleans, Louisiana, a city _______ name will create a picture of beautiful trees and green grass in our mind.