动火作业分几类？
You are creating an ASP.NET Web site. The site contains pages that are available to anonymous users. The site also contains a page named Premium.aspx that provides premium content to only members of a group named Subscribers. You need to modify the web.config file to ensure that Premium.aspx can be accessed by only members of the Subscribers group. Which configuration should you use？（） <location path="Premium.aspx"> <system.web> <authorization> <allow users="Subscribers"/> <deny users="*"/> </authorization> </system.web> </location> 。 <location path="Premium.aspx"> <system.web> <authorization> <allow roles="Subscribers"/> <deny users="*"/> </authorization> </system.web> </location> 。 <location path="Premium.aspx"> <system.web> <authorization> <allow roles="Subscribers"/> <deny users="?"/> </authorization> </system.web> </location> 。 <location path="Premium.aspx"> <system.web> <authorization> <deny users="*"/> <allow roles="Subscribers"/> </authorization> </system.web> </location>。
饲粮
关于搅拌罐式反应器以下说法正确的是（） 容易控制温度和pH。 游离酶不能回收重复利用。 难以控制温度和pH。 单位体积中所含酶的量较多。 传质阻力较低。
进行水泥试验筛标定时，应使用水泥细度标准样品。每个试验筛的标定应取2个标准样品连续进行，中间不得插做其它样品试验。
You are writing a custom dictionary.The custom-dictionary class is named MyDictionary.You need to ensure that the dictionary is type safe. Which code segment should you use？（）
