Explain the usage of the simple present tense in reported speech.

The simple present tense is used in reported speech to convey information or statements that are generally true or habitual. When reporting someone's words or thoughts in the present tense, we often use the simple present tense to maintain the original meaning and tense of the reported speech.

Here are some key points to remember about the usage of the simple present tense in reported speech:

1. Statements: When reporting statements or facts, we use the simple present tense to convey information that is generally true or always applicable. For example:
- Direct speech: "I work as a teacher."
- Reported speech: She said that she works as a teacher.

2. Habits and routines: The simple present tense is used to report someone's habits or routines. For example:
- Direct speech: "He always goes for a run in the morning."
- Reported speech: She told me that he always goes for a run in the morning.

3. Universal truths: The simple present tense is used to report universal truths or general knowledge. For example:
- Direct speech: "Water boils at 100 degrees Celsius."
- Reported speech: He explained that water boils at 100 degrees Celsius.

4. Future events: The simple present tense can also be used to report future events that are scheduled or part of a fixed timetable. For example:
- Direct speech: "The train leaves at 9 am tomorrow."
- Reported speech: She informed us that the train leaves at 9 am tomorrow.

It is important to note that when reporting speech in the simple present tense, we may need to make changes to pronouns, time expressions, and verb forms to match the new context of reported speech.