To teach you to use your eyes.

You should learn to be observing.
Didn't you hear us talking about that oven when Jane brought home the stove ?" "Ye--es.

I had forgotten." "Of course you had.

Now get ready for supper.

To-morrow I will make an oven of stones on the shore and you shall make your custard and you shall have it all to yourself, if you wish, just to punish us for being so mean to you.