Now I will describe the word 'is'. "Is" joins the subject to a description. Any descriptive word can be used but the descriptive word must follow 'is'. It can also be used for actions. 1) The cat 'is' tall. 2) The car 'is' red. 3) She 'is' pretty. 4) He 'is' happy. 5) Learning a new language 'is' difficult. 6)The distance to Montreal is 66km away. How far is it to Montreal? It is 66km away. 7) A couple 'is' walking down the street and they both see a wild fox. (This describes the couple's actions.) The woman wants to know what type of animal it is. (I used 'it' instead of saying 'the wild fox' since the previous sentence already implied that I was referring to the fox. The word also replaces the word fox because I am describing the type of animal.) Although the last sentence is confusing the way to use 'it+is' is fairly simple. Example: 1)The fox is beautiful. = It (the fox) is beautiful. I replaced the object with 'it' and used 'is' to join it to the word beautiful. 2) The building is tall. It is tall. Another thing to keep in mind is that 'it is' and "it's" are the same thing, just the two words are joined. Example: 'It is" raining. = 'It's" raining. This is often used because it is faster to say and depending on what you talking about can be less formal. It is the same as joining 'do not' to "don't" or cannot to can't, or does not to doesn't. If you are writing a formal paper you should always use 'it is' Another word to consider is 'its'. This word is explaining that something belongs to the subject. Example" The fox's leg. = Its leg. This describes something that is owned or possessed by the subject. Similar to saying 'Chantal's house'. Chantal owns the house and the fox possesses a leg. When you uses this word it directs the focus of the sentence on the owned object. I hope that helps.