must
- I must thank ____for ____help.
- We must try ______ best to make our city more beautiful.
- This backpack must belong to _______.
- This book must belong to because it has my name on its front page.
- We must protect plants. They are friends of ______.
- I must thank ____for ____help.
- When you are planting trees, the trees ________ straight in the hole.
- Heavy smog (雾霾 )in eastern and central China seems to get more and more serious.—I agree. Something to deal with it.
- I must return the book to the library. I _____ it for one week.
- How often do I need to feed the dog?——It___food everyday, or it will be hungry.