... DS, when asked "how do you ..." would start with "because ..." and I would say, "because is not an answer to how," and explain what kind of answer I was looking for, and talk about question types and all that.
LOL, some would say there are many options for
how to... and therefore may begin with a qualifier (such as "
Given that..." or "
If... Then..." or even the dreaded "
Because..."). Overthinking? Yes. Many gifted individuals see multiple possibilities, which is great in real life problem solving, brainstorming, and for flexibly in working around unforeseen obstacles, wildcards, and roadblocks... but not so great in test-taking. Gifted individuals may gravitate toward thinking about and focusing on the fringe or edge of any concept... the exceptions to the rules, and any possible inconsistencies/discrepancies. The 80/20 seems to apply.
Affirming the validity of their thoughts and statements, and the important role which this type of thinking plays in an inclusive society (for example, making things handicap accessible) may be a first step.
Inviting the individual to consider the mainstream may a second step, and one which guides their thinking toward answers which tests may be looking for and consider "correct" for the majority of situations.
Approaching this from a different angle, kids may answer with their favorite part of a passage, or with what they may already know which was not in the passage (as though they were having a conversation, not as though they were being tested.) Cutting a "window" in a piece of paper and asking the child to find the best words from the passage which answer the question may help the child focus on answering the reading comprehension question at hand. Once the information is found, the child may construct this into the full sentence needed (for example, "What is a star?"
A star is...)