Good work! It appears you understand the concepts of the exercises.

Although your line quality and elipses is rough, this should improve as you continue to practice these excersises as warm ups before you start your future drawing sessions and as you build an understanding of what you are drawing.

You also seem to have an understanding with the rules of perspective as seen with your work on the box exercises (especially the Rotated and Organic box exercises). It isn't perfect, but thats why there is a 250 Box Challenge.