A city is larger than a town. New York City, Boston, Miami, and Los Angeles are examples of cities. All state or country capitals are cities; cities usually have some significant political, economic or cultural importance. The word town refers to a smaller population center. And a very small population center - even smaller than a town - is called a village.
To complicate things, the central part of a city (especially the main commercial or business area) is called downtown. If you live downtown, you live right in the middle of the main action of the city - and it's more expensive to live downtown than to live in one of the other neighborhoods.
This is another classic exercise that is often performed incorrectly. It is basically the same as the sit up, but at the top of the movement bring the opposite elbow towards the knee. Avoid over rotating, and keep your chest up throughout to avoid excessively rounding your back.