A complex question is a question with a built in assumption.

A classic example is, "Do you still beat your wife?" How would you answer this question? If you say no, that means you used to beat your wife. If you say yes, then you are still beating your wife. This question commits a fallacy. The question should be worded in 2 parts, like this: "did you ever beat your wife? If so, do you continue to do so?" This question does not have a built in assumption, so it doesn't commit a fallacy.

Sometimes an evolutionist might say, "Why are you creationists against science?" This commits the fallacy of a complex question. It should be: "Are you creationists against science? If so, why?"

This is one that you might find in a textbook: "Do you think the horse evolved rapidly, or slowly?" This is a complex question, it has a built in assumption: that horses evolved. The question should be split into two, "Did horses evolve?" and "If so, did they evolve rapidly or slowly?"

And one more: "Which of the 2 contradictory stories of creation do you accept?" But there is only one creation story in Genesis. So the question should be: "Are there two contradictory stories in Genesis?" and "If so, which do you accept?"

Keep an eye out for this fallacy, they can trap you just by using certain words.