—People find it hard to get across the river．—I think at least two bridges         over it．

If the government takes measures to enrich senior citizens’ social and spiritual life, it ____ help develop a truly harmonious society.

---Can you play the guitar?---________.

The manager demanded that the work________ within three days.

— Must I go to medical school and be a doctor like you，Dad?— No，you__________，son．You’re free to make your own decision．