版本有何作用？
You are implementing an ASP.NET MVC 2 application. In the Areas folder， you add a subfolder named Product to create a single project areA. You add files named ProductController.vb and Index.aspx to the appropriate subfolders. You then add a file named Route.vb to the Product folder that contains the following code.01 Public Class Route Inherits AreaRegistration02 03 Public Overrides ReadOnly Property AreaName As String04 Get 05 Return "product"06 End Get 07 End Property08 09 Public Overrides Sub RegisterArea（ByVal context As AreaRegistrationContext）10 11 context.MapRoute（"product_default"， "product/{controller}/{action}/{id}"， New With {.controller = "Product"， .action = "Index"，.id = ""}）12 13 End Sub End Class When you load the URL http：///product， you discover that the correct page is not returned. You need to ensure that the correct page is returned. What should you do？（）
（）是指由水泥、细骨料、矿物掺合料、外加剂和水以及根据性能确定的其他组分，按一定比例，在搅拌站经计量、拌制后、运至使用地点，并在规定时间内使用完毕的拌合物。 A.干混砂浆 。 B.湿拌砂浆 。 C.水泥砂浆 。 D.石灰砂浆。
固定化原生质体、吸附法、包埋法、结合法、交联法
期权
板材的仰焊操作技术最难掌握，不易产生理想的焊缝成型，下列操作规程中不正确的是（）。
