I don’t know when he _______ tomorrow, when hetomorrow ,I will tell you.

Our city has a _____ population .

The scene of the film ____ me of those happy days that we spent together in the beautiful countryside last summer vacation．

We are organizing a lot of activities to celebrate the _______ birthday of the Communist Party of China these months.

Look at the boy running on the playground. Is it David? —- It ______ be him. I saw him go to the teachers’ office just now.