Definition: Craft one correct answer to the question given in input. To make it more interesting, try to use non-stereotypical language if possible. Make sure your correct answer is reasonably long, consistent with the context, and requires common sense (instead of explicit extraction from the context.) In your answer, use as few words as possible from the given context. Use a response that is uncommon/non-stereotypical, so that it is less predictable. To be less repetitive, please vary your language for each question.
Input: Context: I do n't know why , but I suspect it 's because at night it 's dark , and he has become used to falling back asleep , like we all do at night . During the day when it 's light , he wakes up and ca n't put himself back to sleep yet . The other bad thing is that until now , I ' ve let him take his afternoon nap in the swing , which is becoming a problem because I think he is fast approaching the weight limit ( I ' m fairly certain the limit is 20 lbs , and he was 16 about three weeks ago ) . So pretty soon , there will be no swing to nap in .
Question: What 's a possible reason he ca n't put himself back to sleep during the day ?
Output:
Because it 's too bright .