10.79 ordering points

In formal writing and speech, people often want to indicate what stage they have reached in writing or speaking. They do this using the following adjuncts:

first, firstly, second, secondly, third, thirdly, finally, in conclusion, lastly, then, to sum up

• What are the advantages of geo-thermal energy? Firstly, there's no fuel required, the energy already exists. Secondly, there's plenty of it.
• Finally, I want to say something about the heat pump.