How to use c# code inside <% ... %> tags on asp.net page?

I'm writing an asp.net user control. It has a property, FurtherReadingPage, and two controls bound to it: ObjectDataSource and a Repeater. Inside the Repeater I would like to display a hyperlink with an href property set to something like FurtherReadingPage + "?id=" + Eval("Id"). I don't know how to do it inside the page's markup. I can use <% Eval("Id") %> or <% Response.Write(FurtherReadingPage + "?id=") %> alone but I don't know how to mix them.