Listen carefully and fill in each blank with NO MORE THAN TWO word.

Where would we be without muscles? Probably a mess on the floor. Muscles are pretty interesting things. Everybody has lots of them. Some people (36) _________ them better than others. (37) _________want to have really big muscles. The bigger the better. They spend hours in the gym (38) _________ to make their muscles as big as they can. (39) _________ work on the specific muscles they need for their sport. If you look at a hundred-metre runner, you’ll notice they have large shoulder and arm muscles. This is so they can (40) _________ when they run. An interesting thing about muscles is that it takes more face muscles to frown than it does to smile. This means smiling uses less energy, so we should do it more.