If there are trees, the air in our city will be cleaner.
By the time I locked the door, I realized I ________ my keys at home.
You are ________ to write quickly when we have a meeting.
—You look sad. What has happened?—Everyone ________ us to win the match, but we lost.
—Do you know why he didn't ________ a word when he ________ to? —Because he was too nervous.
Our plane is ________ in a few minutes. Please be seated and keep your safe belt fastened.