Ответ:

Выбор определяется значением слова и грамматикой: с исчисляемым существительным во множественном числе употребляется many; после did нужен начальный глагол.

  1. The Alps are not very high.
  2. Nobody knows anything about this fact.
  3. If you walk fairly fast, you won’t miss your train.
  4. The walls around the Kremlin helped to defend it.
  5. The first houses in St Petersburg were wooden buildings.
  6. Can you hear everything the speaker is saying?
  7. I know nothing about this palace. When did it appear?
  8. Are there many cathedrals in the centre of the city?
  9. There are few statues in the hall.
  10. Who founded Moscow?