While walking around your neighborhood, you see your neighbor, who's playing with her dog. The dog is standing up like a person. You're delighted to see that, so you say:
Oh! You trained him to stand on his hind legs?
You're reading a website about penguins. It's written in a kind of scientific style. One part of the page is about how they swim. It says:
Their powerful flippers propel them through the water in search of prey.
animals, hunting, movement, science, written English 
You're reading a web page about penguins written by someone who's really interested in them. The page is explaining penguins scientifically. It says:
Penguins are remarkably well adapted to their icy environment, thanks to millions of years of evolution.
animals, environment, science, written English 
You and your boyfriend are having fun imagining what you will do when you retire. You say:
One day I want to buy a little farm in the country and grow vegetables and raise chickens.
animals, conjunctions, countryside, determiners, dreams, farming, future 