下面说法正确的是（） ["流函数的存在条件是平面不可压，而势函数存在的条件定常且无旋","两条流线的流函数的差值代表这两条线之间的流量，而两条等势线的势函数的产值代表这两条线之间所夹的涡量。","等位线和等势线总是正交的。（速度为0处不一定）","理想流体一定满足质量方程和欧拉方程。（正确，无粘性）"]
影响犯罪的心理因素
岩石物理性质
You create a custom server control named Task that contains the following code segment. You need to ensure that adding a Task control from the Toolbox creates markup in the following format. Which two actions should you perform？（） ["Add the following code segment to the project’s AssemblyInfo.cs file. [assembly： TagPrefix（"DevControls"， "Dev"）]","Replace line 05 with the following code segment. [DefaultValue（"New Task"）]","Insert the following code segment immediately before line 03. [ToolboxData（"<{0}：Task runat=\\"server\\" Title=\\"New Task\\" \/>"）]","Replace line 10 with the following code segment. output.Write("<Dev:Task runat=\\"server\\" Title=\\"New Task\\" \/>")"]
（）是我国人口在国土上一条著名的分界线，其两侧的人口总量差异较大。 ["以长江为界","以黑龙江省黑河至云南省腾冲一线为界","以黄河为界","万里长城为界"]
曹雪芹的家世和生活对《红楼梦》的创作有什么样的影响？
