5 is correct. We stayed beneath the trees as long as the rain continued.
6 is correct. All day long the downhill skiing champion walked, as though she had injured her leg.
7 is incorrect. There should be a comma after faithfully. (Because Judy practiced faithfully, she did well in the figure-skating competition.)
8 is correct. John, after he completed his bachelor's degree in architecture, started and ice arena design company.