Over 20% of the students at that school _____ the habit of smoking, which is beyond imagination.
---Would you like _____ camping with me? ---- I ’d like to. But I’m busy _____ my homework.
---May I take this book out ? --- No, you _____ .
He’s worked there since the shop opened in 1998, _____ ?
She will have a holiday as soon as she _____ the work next week.
The world _____ . Things never stay the same.