钻石模的特点。
参考答案：
由于天然钻石模价格昂贵，非常脆弱，主要用于细微线的拉制。
根据中文提示写出单词，完成句子，每空一词。
小题1:__________, (不幸的是)we didn’t catch the school bus and had to walk to school.
小题2:Whatever your _________(选择) is, I will just follow you.
小题3:The books should be returned no _________ (迟) than next Friday.
小题4:He’d like to buy a present for his grandpa’s ___________(99) birthday.
小题5:Please be careful with these _________ (小刀). They are very sharp.
常用钻头有哪些？
