If you want an easy way to track how many hours have you worked in a day and have a nice report of how much time you are spending working, you will be surprised how it is easily done with Working Hours.
You can start to log your hours by simply saying something like: "Start to log my hours".
When you get your job done, you can close the report by saying: "Close my hours."
To know how much time you have spent on a specific date, just ask like: "How many hours have I worked at 'Day-X'"