选择代用材料时，要有充分的技术依据，原则上应该选用化学成分和性能（）
A.越高越好
B.高低都可以
C.相近或略低者
D.相近或略优者
参考答案：D
—What do you think of the book?
—It’s ______ a book. It serves as (充当)a really good guide to job hunters.
A．would like
B．more than
C．rather than
D．less than
常见的晶面花纹有哪些？聚形条纹与聚片双晶纹有何区别？
