How do you mean? Usually construction geometry is purposely meant not to be selectable. It's only for use inside the sketch itself. Depending upon your layer settings and some other options, you should be able to see any actual geometry sketches you used in your model and select those in the drawing. Just make sure your sketches haven't become "hidden" (greyed out in the model tree). If so, you'll need to unhide them before you can select them in a drawing.
Or am I completely missing the point here? Maybe a screenshot would help us answer your question.