Grammar is how we put words together in a sentence. Each word in a sentence belongs to a particular set or class, depending on how it is used. These classes are called parts of speech. All sentences begin with a capital letter and end in either a full stop, a question mark, or an exclamation mark. These marks, e.g. commas, semicolons, full stops, brackets, and so on, are called punctuation. The term clause is used to describe a group of words that contains a verb, the subject of that verb, and, often, some other words such as an object. · I live in Beijing. · …where I live. · Jessica lived in London at first. · He was living in Chicago that year. · …when he had eaten lunch.