OSI参考模型中，以帧为单位传送数据的是（） ["物理层","数据链路层","网络层","表示层"]
简述激励应遵循的原则。
You are developing an ASP.NET Web page. You add the following markup to the page. You add the following code segment to the code-behind. You need to save the uploaded file and display a message to the user that indicates that the upload either succeeded or failed. Which two actions should you perform？（） ["Replace line 3 with the following code segment. if （FileUpload1.HasFile）","Replace line 3 with the following code segment. if （FileUpload1.FileContent.Length > 0）","Insert the following code segment at line 6. FileUpload1.SaveAs（saveName）；","Insert the following code segment at line 6. FileUpload1.FileContent.CopyTo（new FileStream（saveName， FileMode.Open）；"]
以下哪种反应器仅适合用固定化酶反应（） ["搅拌罐式反应器","鼓泡式反应器","固定床式反应器","膜式反应器","流化床是反应器"]
原始社会的主要道德规范是（）。
简答伟晶岩矿床的岩浆岩条件？
