题目内容：

This article is for all of the teenagers out there. Even though ____ you are years from being fully grown, society regularly expects you to adult. Yes, you are ____ in many ways: many of you drive and do so quite safely, and you handle schedules that would ____ many adults. But you probably cannot process caffeine (咖啡因) as constantly as your parents can because of your still-growing bodies and brains.

I understand it feels grown-up to be drinking a cup of Starbucks. But all of this caffeine may worsen your anxiety, affect tonight’s sleep and tomorrow’s school performance, ____ nutrient absorption and even cause real trouble when mixed with alcohol. The following four aspects may well ____ the theme of this article.

The power of caffeine

Caffeine is widely considered a drug that is socially acceptable, universally used, even cool, but it still causes ____ symptoms such as headaches, fatigue and a lack of attention when removed from coffee-addicts’ diets.

How much is healthy?

Caffeine is by no means a nutrient; you do not need it to be healthy. ____, it is a substance that can leave you lacking nutrients because it has been shown to reduce calcium (钙). Caffeine probably causes the body to release water. And the more caffeinated drinks you consume, the less likely you are to drink water. So experts say that adolescents should consume ____ amounts of caffeine a day (≤100 mg).

Caffeine’s ____

According to the Centers for Disease Control and Prevention, about 65 percent of middle and higher schoolers are ____ to insufficient sleep on school nights. Some of their sleep problems can be mainly attributed to (归因于) caffeine, which can remain in the body for seven hours after ____, thus causing teens’ worse performance the next day. It is widely assumed that adequate sleep ____ proper growth and brain development. During childhood and adolescence, the brain goes through a period called synaptic pruning (突触修剪) when unnecessary connections are promoted.

Caffeine labelling

Caffeine is not listed on the Nutrition Facts column on food labels because it is not a ____. It may be listed as an ingredient, but the amount is not required. Caffeine is now added to foods such as gum, candy and water, along with makeup and beauty products that ____ to reduce swelling (肿块).

Taste preferences and eating habits are often cultivated in childhood and adolescence, so teens, when you consume sweet, caffeinated drinks every time you feel sluggish (无精打采的), you are creating a pattern that may be hard to break as an adult. It is advisable to come up with other ____ ways to boost energy so that you can master adulting better than many adults.

1.A. potentially    B. necessarily    C. developmentally    D. materially

2.A. mature    B. experienced    C. productive    D. disciplined

3.A. delight    B. frustrate    C. liberate    D. exclude

4.A. promote    B. assist    C. intensify    D. discourage

5.A. call for    B. account for    C. turn to    D. appeal to

6.A. withdrawal    B. addiction    C. nutrition    D. infection

7.A. Therefore    B. Instead    C. Moreover    D. Otherwise

8.A. initial    B. sufficient    C. moderate    D. stable

9.A. reputations    B. confirmations    C. implications    D. disadvantages

10.A. subjected    B. alerted    C. reduced    D. opposed

11.A. stimulation    B. concentration    C. excitement    D. consumption

12.A. results from    B. contributes to    C. benefits from    D. attends to

13.A. therapy    B. material    C. nutrient    D. substitute

14.A. fail    B. appear    C. promise    D. happen

15.A. instructive    B. comprehensive    C. extensive    D. alternative