People used to think that learning two languages created confusion in the mind. Far【C1】______it was thought, to get one right than bother with two. An even more extreme and【C2】______view was that learning two languages caused a kind of mental illness or dual personality. Some studies did seem to【C3】______the idea that learning two languages could be problematic; early researchers noted that bilingual people tended to have smaller vocabularies and slower access to words. But these myths and【C4】______disadvantages have now been overshadowed by a【C5】______of new research showing the【C6】______psychological benefits of learning another language. And these extend way【C7】______being able to order a cup of coffee abroad or ask directions to your hotel. First, Language centers in the brain actually grow as a result of successful language learning. The better you learn, the more those【C8】______areas of the brain grow. Second, bilingualism【C9】______Alzheimer's disease in susceptible people by as much as five years. Seems unbelievable,【C10】______the studies are continuing to support this result. Third, being bilingual can lead to【C11】______listening skills, since the brain has to work harder to recognize different types of sounds in two or more languages. Fourth, you may become more language 【C12】______. Infants in bilingual households can distinguish languages they've never even【C13】______before. Just being 【C14】______the different sounds in, for example, Spanish and Catalan, helps them tell the difference between English and French. Fifth, it can【C15】______your memory. Babies brought up in a bilingual environment have stronger working memories than those brought up【C16】______only one language. Sixth, bilingual people can【C17】______from one task to another more quickly. Seventh, bilinguals have stronger control over their【C18】______and are better able to limit distractions. Furthermore, it can help develop new ways of seeing and improve your first language etc. These are all quite apart from the benefits of【C19】______yourself in another culture, and of seeing your own culture from the【C20】______of another. You may well get something like ' a second soul' from learning another language.

【正确答案】 D

【答案解析】解析：本句空格前有表示强调的助动词did和情态动词seem，后半句中还有另一个情态动词could，这些词都表明一种推测，表明主语Some studies所描述的观点是可能成立的。后半句有提到双语者词汇量小，学习词汇慢，这也说明了学习双语确实会带来一些不良影响。因此选D项back up“支持”，即一些研究证实学习双语可能会导致某些问题。