1.  Firstly, energies would be cut down when spent too much on how to make us attractive in order to make a good impression on our girlfriend or boyfriend , as a result , we put less efforts on our study .

2.  The horse can learn many things in a short time which associated with the command which he has to do; the shepherd dog does not know as much about most things as some other dogs, and yet he comprehends it very well on how to take care of sheep.