3.【解析】They should include a quiet “rest” time in the daily schedule of their children. /They should give their children a rest time every day. 从第三段的最后一句Dr．Crosby suggested that parents include a quiet “rest” time in the daily schedule of their children to allow kids to nap if needed．可知。
4. 【解析】How did the experts carry out their study. 由第四段第一句话可知答案。
5. 【解析】克罗斯比博士希望新发现会鼓励其他调查者研究小睡是如何影响孩子们白天表现的。注意which定语从句以及performance（表现）的翻译。
