过冷度越大，固溶体合金的形核率越大，越容易获得（）的晶粒。
A.粗大
B.细小
C.不均匀
D.不一定
参考答案：B
This book is said to be a special one, which ______ many events not found on other history books. [ ]
A. writes
B. covers
C. prints
D. reads
AVM头痛的原因（）
A.供血动脉、引流静脉或窦的扩张
B.AVM出血
C.脑积水
D.颅内压增高
E.术后脑血管源性水肿
