//here we have one resultset
var largeBlogs = context.Blogs.Where(b => b.Posts.Count > 5);
foreach (var blog in largeBlogs) //we use the result set here
{
//here we try to get another result set while we are still reading the above set.
var postsWithImportantText = blog.Posts.Where(p=>p.Text.Contains("Important Text"));
}