Only when I left my parents ________ how much I loved them.
________ by a group of children, he felt happy.
When I was a little boy, I lived in a small fishing village. The visit to the village reminded me of the _______ of childhood.
I took a _______ from Beijing to Shanghai last year.
Something must be done to prevent factories ________ poisonous gases so as to keep the city ________.
He was absent for weeks, so he had a lot of homework to ________.