Mr Simson sends a letter to his friend.
Mr Simson is sending a letter to his friend.
Mr Simson will send a letter to his friend.
Mr Simson sent a letter to his friend.
Mr Simson sends a letter to his friend.
Mr Simson is sending a letter to his friend.
Mr Simson will send a letter to his friend.
Mr Simson sent a letter to his friend.