Tom took a taxi to the airport, only _____ his plane high up in the sky.
_____ prepare for the coming exam, Dave stays up late every night.
We can’t put off _____ a plan. We should do it right now.
--- The twin boys look sad. Let’s _____ . --- OK!
I saw a dog _____ on the side of the road when I passed by.
To _____ surprise, no one volunteered for the position of monitor.