---Listen! The fire engine is roaring! (消防车吼叫) --- Oh, there ______ be a fire somewhere. How terrible!
I hurried________I wouldn’t be late for work.
It’s not until no enemies were left that they________ .
While playing ping-pong, our eyes see the ball coming, judge its speed and then hit it back ________ it should go.
I was about to leave my house________the phone rang.
.________they were singing, the teacher came in.