Fill in the gaps with the correct form of the words in brackets.
Dogs are thought to be intelligent creatures. They can remember approximately 165 words on average. This includes 1 ... \(VISION\) signals and other signs. A trained dog can learn even more words, up to 250.
Some studies demonstrate that dogs are as clever as a two-year-old child. This has been measured in a couple of ways. Firstly, a dog knows about the same number of words as a child of this age. 2 ... \(ADDITION\), there is a mirror test that is used to measure 3 ... \(AWARE\). Dogs never really understand their 4 ... \(REFLECT\) in the mirror. They think it’s another dog. Children are like this, too, until they’re about three.
Like many other animals, dogs sense some things far better than humans. They’re often 5 ... \(ABILITY\) to understand 6 ... \(SOCIETY\) situations faster, such as who is the most dominant animal in a pack.