A
It is estimated that more than half the world's population is bilingual (双语的), and in an increasingly globalizing world, there are obvious benefits of speaking more than one language. However, for many years, parents were advised not to teach their children to speak more than one language from birth. Learning two or more languages simultaneously (同时) was believed to cause confusion and slow down academic development. While it is certainly true that children who are learning to speak more than one language as their mother tongue will often mix the languages up or speak a little later, these are temporary problems, and there is no reason to avoid teaching a child more than one language.
In fact, there are plenty of reasons to encourage your child to become bilingual from birth. As well as the obvious benefits of being able to communicate with more people, and the possibility of earning more money, children who speak more than one language have been shown to score more highly in achievement tests at school. This is true for mathematics as well as tests of verbal (言语的) skills.
And in later life it has been found that bilinguals, on average, will tend to develop Alzheimer's disease five years later than monolingual speakers. Speaking three or more languages offers even more protection. It seems that the increased number of connections within the brain allows bilinguals to cope better with brain damage.
But is it too late if you haven't already learned a second language in childhood? It used to be thought that the adult brain was very fixed, but recent research has shown that we continue to develop new connections in the brain throughout our lives, meaning that it's perfectly possible to learn another language to a high standard. Older learners are less likely to have nativelike pronunciation, but they are better at learning vocabulary as they are able to use far more skills and strategies than children. And learning a language is like using a muscle—the more you use it, the stronger it gets, meaning that you will find your third language easier than your second, and so on.
文章论述了学习双语的好处，如延缓阿尔茨海默症的发生，使学习过程变得越来越容易等。
1．Why shouldn't parents be discouraged from teaching their children to be a bilingual?
A．Children's confusion over two languages will not last long.
B．Children will not mistake one language for the other.
C．Parents should begin to teach a second language early.
D．Parents' guidance will help children tell two languages apart.
答案：A
解析：细节理解题。根据第一段中的these are temporary problems可知，孩子因学两种语言而感到困惑的情况不会持续太久，因此家长不应该劝阻他们的孩子学习两种语言，故选A项。
2．Which of the following is NOT a possible benefit of being a bilingual?
A．A bilingual is less likely to develop Alzheimer's disease.
B．A bilingual child may do well in mathematics at school.
C．A bilingual will probably make more money.
D．A bilingual child owns relatively good language ability.
答案：A
解析：推理判断题。根据第三段中的“And in later life it has been found that...than monolingual speakers.”可知，双语者比只说一种语言的人可能要晚五年得阿尔茨海默病，但这并不能说明双语者不太可能得阿尔茨海默病，故选A项。
3．Compared with children, adult language learners ________.
A．are slower at learning a second language
B．are more skilled at building vocabulary
C．are more likely to acquire a native accent
D．are slower at making logic connections
答案：B
解析：推理判断题。根据最后一段中的“Older learners are less likely...and strategies than children.”可知，年龄较大的学习者不太可能学会像母语使用者一样的发音，但他们会在学习词汇方面做得更好，因为他们在这方面比儿童更擅长使用技能和策略，故选B项。
4．What can be learned from the passage?
A．A bilingual child will speak both the languages badly later in his life.
B．Learning a second language certainly contributes to your body fitness.
C．Connections within adults' brain will permanently stop developing.
D．With each language learned, the learning process will become easier.
答案：D
解析：细节理解题。根据最后一段中的最后一句可知，学习一门语言就像使用肌肉——你用得越多，它就变得越强壮，这意味着你会发现学习第三语言会比学习第二语言更容易，即随着更多种语言的学习，学习过程将变得越来越容易，故选D项。
