After studed from Grammar Excercise

Yesterday, I studied grammar exercise through internet website. This website had various tests and much information. Especially, I concentrated that studied Basic Sentence Parts in many parts. Above all, I was hard that could not understand structure word. For example, (Extraction from Body Parts: Quiz Four in Basic Sentence Parts)

9. What is the full tense classification of the sentence "I will have completed my dissertation by May"?
A. future perfect
B. future perfect progressive
C. future
D. future passive
E. future passive perfect

I did not understand what was mean of perfect progressive. So, first of all, I started to study structure words. After studied to them, I restarted to solve basic part quizzes. As a result, I was more quickly understood and learned like ‘Structure of grammar’, ‘Grammar’s uses’. Moreover, I could easily solve more many quizzes. Even My English skill is low level, but I will learn many grammar skills through this website and will more upgrade my English level.