Fill in the gaps in the following sentences with articles if

Fill in the gaps in the following sentences with articles if necessary. I joined the experiment as (1)... volunteer. Our mission was to transport (2) ... huge bluestone 240 miles to Stonehenge. We discovered dragging (3) ... bluestone was much more difficult than we expected. (4)... boats were too small to transport it. Finally, the journey was delayed as (5)... tired helpers dropped out. I think, next time they should invite (6)... more enthusiastic people, if they want to succeed.