有关骨纤维异常增殖征叙述正确的是（）

A.病理上由异常增生的纤维组织及其纤维化骨组织构成

B.好发年龄小于40岁

C.典型表现为较广泛的囊状磨玻璃样改变

D.皮质变薄、髓腔增大

E.骨体常发生畸形

In relation to the basic legal system of China:

(b) state any one of the rules regarding the validity of a contract provided for in the judicial interpretations on the Contract Law by the Supreme People’s Court. (4 marks)