晶体的特性有三：1.有固定的几何外形；2.（）；3.（）

参考答案：A

参考答案：平弧型；倾斜型；混合型

答案：D

解析：

参考答案：In our life, opportunities don’t come often.They often come quietly and pass by without being noticed.Some people complain that opportunities are few.They always admire those people who make a hit or succeed by seizing some opportunities.Owing to the contingency of opportunities, we should value and treat them with care.
Everyone desires for success, but when it comes to the way to success, different people have different opinions.Some people think that opportunity is the first factor leading to success.Almost all successful people have come across some valuable opportunities.It should be noticed that opportunity won’t wait for you all the time.If we can’t notice and seize it, others do.The ways for different people to treat opportunities lead to different results.We must take advantage of opportunities when they come.That means we should be well-prepared all the time, then we can seize opportunities and achieve success.
In my opinion, there are plenty of opportunities for everyone in the society, but not only those who are prepared adequately can make use of them.As the saying goes “God helps those who help themselves.” No matter whether there’s opportunity or not, what we should do is to work hard.Only in this way can we find and seize opportunity when it occurs.