Переведите предложения на русский, определяя функцию инфинитива

  1. To explain this simple fact is not so very easy.
  2. We are to study the main laws of physics.
  3. The author was to read a paper at the conference.
  4. The next step will be to produce a diagram of the system.
  5. Glass which is to be used for lenses must be almost colourless.
  6. The exact level is hard to calculate.
  7. The books by Pawling are interesting to read.
  8. The experimental results are few and not easy to interpret.
  9. He must have found out about the conference from the newspaper.

10.The explosion must have occurred long ago.