Time expressions are words or phrases that help indicate when an action occurs. They can refer to specific times, such as Monday, January, or 2023, or more general periods, like yesterday, now, or soon. These expressions help clarify the timing of events in sentences, making communication clearer. There are different types of time expressions, including past, present, and future indicators. For example, phrases like last week or in two days specify when something happened or will happen. Using time expressions effectively enhances understanding and provides context in both spoken and written language.