A、B两种有机物组成的混合物，当其质量相等时，无论A、B以何种比例混合，完全燃烧时产生H₂O的量均相等，符合这一条件的组合是  (   　 )

①同分异构体     ②同系物     ③最简式相同     ④含氢质量分数相同

⑤分子中氢原子数相同          ⑥分子中氢、氧原子数分别相同

A．①③④      B．①②③ 　       C．①⑤⑥　　　       D．②④⑥

Napping is one of the best, most underused tools for busy people. It is frowned 62 by many people and is viewing as something for the elderly and children. Mention napping and you could be seen as lazy, depressed and 63 to work. The majority of people experience drowsiness in the afternoon and notice their productivity and 64 starting to slip and napping will help 65 this and fight the 66 of fatigue such as stress and a lack of mental 67 .
Research on napping is 68 showing positive effects. The results suggest, for example, 69 napping can make you more 70 , reduce stress and improve 71 functioning compared to working all day without rest. A mid-afternoon sleep means that productivity can last long into the night.
Finding 15-30 minutes in a day can sometimes seem difficult, 72 , doing so could mean a great deal to your productivity. Even 10 minutes a day will be better than nothing at all, and may give you the 73 you need to be successful. If you want to give it a try, make sure you can find a 74 place before setting your head down. If you can feel secure and let go, then the nap will be even more 75 .
A lot of people who wish to start their own businesses but are currently working 9-5 will benefit 76 a nap. The majority of the work on their own business will be done after 5pm and it is hard to stay 77 and inspired at this time. Taking a nap during a 78 at work or just after finishing work could 79 increase your 80 levels, allowing you to 81 your own business after the 9-5 grind.

A．farther

B．fabricate

C．suspend

D．further