--I wonder why everybody looks at me strangely when I cross the road. --In this city, you have to wait for a walk _____ to cross the road.
She knew nothing about his journey _______ he was likely to be away for three months.
“How did the robber get in?” “______ an open window on the first floor.”
_______ reading the letter, what has he done?
The lift in that tall building went wrong and got trapped _____ floors. People in it had no way to get out.
In the west, people make _______ a rule to send Christmas present to their relatives and friends.