Many students are very uncomfortable in this state of partial understanding,
like a beginning rock climber who wants to be in stable equilibrium at all times.
To learn effectively one must be willing to leave the cocoon of equilibrium. So
if you don't understand something perfectly, go on ahead and then circle back.
In particular, an example will often be easier to follow than a general statement; you can then go back and reconstitute the meaning of the statement in
light of the example. Even if you still have trouble with the general statement,
you will be ahead of the game if you understand the examples. We feel so
strongly about this that we have sometimes flouted mathematical tradition and
given examples before the proper definition.