腔肠动物生活在水中，它们的结构简单，有____ 无____  ，常见的种类有____ 、____ 。

如图所示，内壁光滑长度为4l、横截面积为S的汽缸A、B，A水平、B竖直固定，之间由一段容积可忽略的细管相连，整个装置置于温度27℃、大气压为p₀的环境中，活塞C、D的质量及厚度均忽略不计．原长3l、劲度系数 $k=\frac{3p_{0}S}{l}$ 的轻弹簧，一端连接活塞C、另一端固定在位于汽缸A缸口的O点．开始活塞D距汽缸B的底部3l．后在D上放一质量为 $m=\frac{p_{0}S}{g}$ 的物体．求：

Importance of College Education

    During the high school career, students may begin to question the importance of a college education. They might find themselves asking, “Why is it important to go to college?” The answer is that, more than ever, college graduates enjoy much greater opportunities available to them than those who have not received a college education.

    For many high school students, being able to immediately generate an income after graduation is an appealing thought. They may also be affected by the rising cost of tuition, and while it is true that a higher education may be one of the largest expenses you will ever face, the importance of a college education has become quite evident in terms of earning potential within today's economy.

    Why should you go to college? One important answer to this question is more opportunity. As opposed to generations of the past, high school graduates today are unable to obtain high-paying jobs that were once available. The U.S. has been transformed from a manufacturing-based economy to an economy based on knowledge, and the importance of a college education today can be compared to that of a high school education forty years ago. It serves as the gateway to better options and more opportunity.

    There are additional reasons as to why it is important to go to college. When students experience a post secondary education, they have the opportunity to read books and listen to the lectures of top experts in their fields. This encourages students to think, ask questions, and explore new ideas, which allows for additional growth and development and provides college graduates with more opportunities in the job market over those who have not experienced a higher education.

    The importance of a college education is also stressed because of the opportunity to gain valuable resources during the study. The more connections which are collected during your college career, the more options you will have when you begin your job search. Once you have ended your job search and have started your career, however, the importance of a college education has not been exhausted. Having a college degree often provides for greater promotion opportunity.

    So, why should you go to college? The reasoning does not begin and end with the job aspect. A good education is beneficial from many different viewpoints, and though the importance of a college education is quite evident for many high school students, what is often not as clear is how they will pay for that education.