A prefix is a series of letters, or a word, that is added to the  beginning of a word and changes the meaning. For example, in the  word midnight, mid is the prefix.
The more vigorous an activity, however, the more calories youâll burn. Changes in body weight are related to both the duration and intensity of play. Playing singles tennis at average intensity expends 300-600 kcal/h, while high intensity tennis training expends 450-900 kcal/h. Diabetes. The incidence of diabetes worldwide of persons aged 20 or above in 1995 was 4% (approx. 135 million), a figure that will increase to approx. 5.4% (300 million people) by 2025.
Often tennis professionals are asked how to keep score in the game of tennis. Unfortunately, there is no simple answer. The explanation provided below may prove useful. In the game of tennis  points make up a game, games make up a set, and sets make up a match. POINTS. A point is scored when someone makes an error, hits past the opponent, or forces the opponent to make the error. In scoring, the servers points are always given first.