A:william I had the domesday book compiled because he wanted to have a reliable record of all his land ,his tenants and their possessions and to discover how much his tenants could be asked to pay by way of taxes.

• 答:所有的土地拥有者；或大或小；都要对他们手中的土地；不仅要宣誓效忠于直接领主；而且要效忠与国王.