用括号内动词的适当形式填空。
1. Today Chinese _____ (speak) by more and more people around the world.
2. An English speech _____ (give) to the children tomorrow.
3. —Did you go to Lily's birthday?
    —No, I _____ (not invite).
4. This kind of food must _____ (keep) cool. Clean and dry according to the instruction.
5. The dog _____ (train) to understand different instructions for two years.