Theory
At A-level, it is necessary - but not sufficient - for students to both separate facts from opinions and be able to demonstrate a sound knowledge of these facts.
Sociology, at this level, is not a simple memory
test ("If I can memorise enough facts I will pass the course"), but clearly factual
knowledge is very important.
However, sociologists are interested in how "facts" are produced, by whom and for what purpose. In this respect, sociologists ask theoretical questions.
We can only explain facts by constructing possible explanations (theories) and then testing our theory against reality (facts).
For example, a very basic theory in this instance might be that "If a man and a woman are both in their teens when they marry, they are more likely to divorce at sometime in the future" (something that, statistically, happens to be true).
Another example might be the fact that men have larger brains than women. A theoretical question here might be to try to explain why is this a fact (the answer is that, biologically, men are generally larger than women. In terms of brain size to average body weight, female brains are actually proportionately larger ) and, sociologically, whether this fact has any significance for male / female behaviour.