【单选题】Create a variable that is connected to the simulation PLC, and realize that the variable decreases from 100 to 0, and the defined variable type is ( ).
【单选题】在吸附层析中,弱酸性物质应在( )性下吸附,( )性下洗脱。
【单选题】下列部件中不属于执行部件的是______。
【单选题】Create a variable to connect with the simulation plc, realize the variable decreasing from 100 to 0, and define the variable type ( ).