单选题 .  Bilingual (双语的) education in schools has long been a political hot potato—it was banned in California by a 1998 ballot measure, which the state Senate is now asking voters to repeal. But politics aside, there's an increasing amount of scientific support for the benefits of knowing at least two languages.
    Now, a new study published by the Annals of Neurology finds that you don't even need to learn that second (or third, or fourth) tongue at a very young age: Picking up a new language even a little later in life can have serious cognitive (认知的) benefits for the aging brain.
    Many recent studies have pointed out that bilingualism seems to be good exercise for the brain and later in life might even help delay the onset of dementia. But what if it's a self-selecting crowd? What if the people who learned two languages are just smarter to begin with? To help rule that factor out, researchers at the University of Edinburgh in Scotland studied 853 people who first took an intelligence test in 1947 when they were about 11 years old as part of a group called the Lothian Birth Cohort 1936, and retested them again around 2008 to 2010, when they were in their early 70s.
    A total of 262 of the seventy-year-old reported having learned at least one language other than English enough to communicate in it. Of those, 195 said they learned it before age 18; 65 said they learned it thereafter. The researchers gave the participants a battery of cognitive tests, including tests of their verbal reasoning, their vocabulary and reading abilities, their verbal fluency and their ability to process information quickly. They found that bilingual speakers performed much better than expected from their baseline cognitive ability, particularly in reading and in general intelligence. And those who knew three or more languages performed even better.
    Learning a language seemed to make as much difference in people's later-in-life cognitive decline as a gene that's been tied to risk of Alzheimer's disease and smoking habits.
    These participants mostly learned their second languages after age 11. The results actually make a very compelling point—you don't have to be a fluent speaker of a language to get the benefits, and you can start later in life, too.1.  The phrase "hot potato" in Para. 1 is closest in meaning to ______.