At the same time, other students in the same class already have the skill down cold, so further practice for them is a waste of time.
同时，同一个班级的其他学生可能已经熟练掌握了这项技能，所以继续练习对他们来说只是浪费时间。
That ever-expanding content is the crux of the social studies teacher's dilemma: How to cover every topic with limited class time?
不断扩大的教授内容是让社会老师进退两难的难题：如何在有限的课堂时间里做到面面俱到呢？
The First time value is the time taken for constructing the first reflection replacement class, which includes the time to load and initialize the classes in the framework code.
第一个时间值是构建第一个反射替代类所花费的时间，这个时间包括装载和初始化框架代码中的类的时间。
This is an improvement over having to write a class any time an anonymous inner class is needed and can help keep the code more self-documenting.
相比于每个匿名内部类都要对应一个类的做法来说，这种方式是个极大的改进，同时也使得代码的可读性更好。
In between those two parts I will ask that anyone who is shopping the class and would like to leave at that time do so then.
在前后两部分之间，请来试听并且想离开的同学在那时候离开，如果你能尽量等到那个时候。
And I am not going to take the time to solve it because I think that is a waste of class time, but those are the three unknowns.
但我并不打算把解这几个方程，我觉得那会是浪费课堂时间，但那是三个未知式。
The challenge is for the work you are going to be doing at the class time we are doing to spend together.
这一挑战是针对，我们要一起在课上，完成的任务提出的。
The LTMemory class represents an area of memory where the time to instantiate an object is the combination of a fixed allocation time and a variable initialisation time.
LTMemory类表示这样的内存域，在这里实例化一个对象的时间等于固定的分配时间加上不定的初始化时间。
The Plugin class is the abstract superclass of all plug-in run time class implementations (see Listing 2).
plugin类是所有插件运行时类实现的抽象超类(请参见清单2)。
If all goes well, it is time to instantiate the class and run its main method.
如果一切正常，那么就可以实例化这个类并运行其main方法了。
The Client class indicates at any given point in time if it is currently involved in an ongoing request.
client类在任意指定的时刻都指出了它是否正在参与进行中的请求。
Another approach (which the Benchmark class USES) is simply to execute the task continuously for a predetermined, reasonably long time.
另一种方法是在一个预先确定的长度合理的时间段内连续执行任务(benchmark类就使用这种方法)。
The disadvantages are that every time a new attribute is added anywhere in the class hierarchy a new attribute must be added to the table.
缺点是每次在类层次结构的任何地方添加一个新属性时都必须将一个新属性添加到表中。
We interview people how do they thinkabout broadcasting class (this is a new class in our school) and all projects are going to show on TV, cause we’ve bought the time.
我们采访了一些人，让他们谈谈对播音课(学校新开设的课程)的感受。这个节目不久将会播出。
Probably the best way to avoid their creation during the program is to avoid using reflection services to map class, field, or methods from strings during the time-critical parts of your application.
或许避免在程序执行期间创建这些类的最佳方式在于，避免在应用程序的时间关键型部分使用反射服务来从字符串映射类、字段或方法。
The lack of middle-class income growth during that span is "the defining issue of our time," Mr. Summers has said, in a tacit admission that liberals were ahead of him on this issue.
萨默斯表示，在这段时期，中产阶级收入增长的缺失是“我们这个时代最重要的议题，”这事实上是承认，自由派在这个议题上要更胜他一筹。
The current strategy for maximizing performance and convenience is to retrieve metadata for a particular table the first time an instance of the class that maps to that table is instantiated.
为了使性能最大化和更加便利，目前的策略是从某一个表中提出元数据，先把一个类的实例映射到那个表上，用来初始化。
Now, Brazil's economy is booming and the growth of the middle class, which included the majority of Brazilians for the first time in 2009, is changing every facet of life.
现在，巴西经济蓬勃繁荣和中产阶级人口成长(2009年首次涵盖半数以上的巴西人口)，正在改变生活的每一层面。
The message receiver also is responsible for dealing with the message accordingly, and most of the time will hand this message to a service implementation class for processing.
消息接收者同时也负责对消息进行相应的处理，大部分时候都会将此消息传递给服务实现类进行处理。
Because the image is always running, any addition, deletion, or update of a method in any class occurs at run time.
因为它总在运行，对任何类中方法的任何添加、删除或更新操作都发生在运行时。
The name of the class used for hard real-time threads probably gives you a clue about how it is implemented by the JVM; we'll discuss this more when we get to memory management.
从这个类的名称中，你或许能够获得JVM如何实现硬实时线程的一些线索；讨论内存管理的时候，我们还会再详细地讨论这个问题。
The run-time system is responsible for loading the service endpoint class and instantiating it.
这个运行时系统负责装载服务端点类以及服务端点类的实例化。
A generic technique to avoid class-loading delays during the time-sensitive parts of your application is to preload classes during application startup or initialization.
一种在应用程序的时间敏感型部分避免类加载延迟通用技术是，在应用程序启动或初始化期间预先加载类。
I believe the time is some of the best-spent time I can give to the class.
我相信这些时间是我所能够给予同学们的最佳时间之一。
The execution model is a bit strange: The test class is reinstantiated every time a test method is executed.
执行模型有点奇怪：每次执行一个测试方法的时候，都要重新实例化测试类。
A general problem with reloading classes this way is, that the old and new class versions are available at the same time and have to be carefully handled by the framework.
不过这种方式重新加载类存在一个普遍问题，即类的新老版本可能同时存在，框架必须小心处理这一问题。
One of the most popular and lucrative part-time jobs is to tutor, either for a college-prep class or a specific subject.
最受欢迎、也最有利可图的兼职工作之一就是为大学预科班或某一科目做家教。
The idea behind these tools is that you can use an existing class as the template for your run-time class generation.
这些工具背后的思路是：可以将现有的类用作生成运行时类的模板。
If so, it returns the same class it returned last time (that is, the class stored in the cache).
如果相同，就返回上次返回的类(即保存在缓存中的类)。
If so, it returns the same class it returned last time (that is, the class stored in the cache).
如果相同，就返回上次返回的类(即保存在缓存中的类)。
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