题干

在酿制果醋的过程中,下列相关说法正确的是(  )。

A:果醋的制作需用醋酸菌,醋酸菌是兼性厌氧型细菌,需先通一段时间氧气后密封

B:在发酵过程中,温度控制在18~25 ℃,发酵效果最好

C:当氧气、糖源充足时,醋酸菌可将葡萄中的糖分解成醋酸而酿制成果醋

D:醋酸菌对氧气特别敏感,仅在深层发酵时缺氧影响代谢活动

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答案(点此获取答案解析)

C

同类题2

根据短文理解完成下列各题。
   March 16 is World Sleep Day. This year's slogan is “Breathe Easily, Sleep Well”. Its aim is to celebrate the *benefits of good and healthy sleep.
   Fangfang, from Liaoning, just became a high school student last September. She gets up at 5:30 a.m. every day and goes to bed at about midnight. Fangfang feels sleepy all the time. “I want to finish all my homework first,” she said.
   Sleep is like food for the brain. Enough sleep helps the body and brain grow and develop. According to the National Sleep *Foundation in the US, adults need seven to nine hours of sleep every night. For students who are 10 to 17 years old, a healthy amount is about eight to nine hours every night.
   But many students don't get enough sleep because of early school start time and heavy homework. About 80 percent of middle school students don't get enough sleep, the China Youth and Children Research Center reported. For some students, they want to sleep early, but they keep worrying about their schoolwork and can't fall asleep quickly. For others, they may even have insomnia, and usually they have to ask the doctors for help.
   These sleeping problems greatly *affect people's life. Some doctors found out that *lack of sleep for teenagers lead to poor grades. Students without enough sleep cannot pay attention in class or do well in sports. Also, they often become anxious easily.
   Luckily, with good sleep habits, it is easier to fall asleep. Some of these good habits include *avoiding drinks that make people excited late in the day, going to sleep at the same time every night, and sleeping in a comfortable place that is dark, quiet, and neither too warm nor too cold.
   More tips to get a good night's sleep:
   Exercising during the day. You'd better do sports three hours before going to bed.
   Don't eat big meals before bedtime. Drink a warm glass of milk. If you stay awake worrying about things, try making a list of things that you need to do before you go to bed.