Although type annotation is not required , using it helps prevent errors associated with accidentally storing the wrong data in a variable and can increase program execution speed 尽管类型批注不是必须的，但使用它有助于避免与在变量中意外存储错误数据相关的那些错误，并可提高程序执行的速度。
Way translate and ask me whether foreigner reach pyongyang go gold the bronze statues of chairmans present a bunch of flowers at first mild and roundabout , certainly this is to volunteer instead of being necessary 途中翻译委婉地问我，外国人到平壤后通常都会首先去金主席的铜像前献上一束鲜花，当然这是自愿而不是必须的。
Way translate and ask me whether foreigner reach pyongyang go gold the bronze statues of chairmans present a bunch of flowers at first mild and roundabout , certainly this is to volunteer instead of being necessary 途中翻译委婉地问我，外国人到平壤后通常都会首先去金主席的铜像前献上一束鲜花，当然这是自愿而不是必须的。
It is requested , but not required , that you contact the authors of the document well before redistributing any large number of copies , to give them a chance to provide you with an updated version of the document 在你对文档副本进行大量再发布前取得与文档作者良好的联系，这虽然不是必须的，但是是有必要的，这样你就有机会得到他们提供的文档的最新版本。
In ejbs with rmi - iiop you have the option although you are not required to of including persistence operations in an outer transaction scope if you use entity beans or session beans with mapper objects if you so choose 如果您使用带有mapper对象的实体bean或会话bean （如果您这样选择的话） ，在采用rmi - iiop的ejb中，您就可以选择（尽管不是必须的）在外部事务范围内是否包括持久化操作。
This is not a must , however ; some utilities simply return 1 for any error condition and 0 for success , whereas others classify errors into categories , and return one of a smaller range of codes , say 1 , 2 , or 3 , depending on the category 不过这不是必须的；有些实用程序对任何错误条件都简单地返回1 ，若成功则返回0 ，而其它实用程序则将错误分类，并根据类别返回较小范围代码（比如1 、 2或3 ）中的一个。
What this means is that most vertical applications are a mere recompilation away from running equally well on linux , freebsd , sunos , irix , aix , or indeed on mac os x ; in some cases even this step is not necessary , since abis application binary interfaces support foreign binaries 这意味着什么呢，大部分垂直应用程序只需要重新编译就可以很好地运行于linux 、 freebsd 、 sunos 、 irix 、 aix ，当然也可以运行于mac os x ；有时连这个步骤都不是必须的，因为abi （应用程序二进制接口）支持外来的二进制文件。
