Cách sử dụng
A stopwatch is a device used to measure the amount of time it takes for an event to happen. It can be used to time a race, to keep track of how long it takes to complete a task, or to time any other activity that requires precise measurement of time. A stopwatch usually has a start and stop button that you can press to begin and end the timing of an event. It is commonly used in sports and in scientific experiments.