Ответ:

  1. A: I think there will only be online schools in the future.
    B: b I agree with you.
  2. A: Do you like surfing the Net?
    B: b I love it.
  3. A: This is a great website, isn't it?
    B: b I like the idea.
  4. A: I think there is too much pollution.
    B: a You're right.