题目

As a young adult, Noah Webster was a teacher. At that time, the colonies were fighting for independence from Britain. Yet the books that American children used in school all came from Britain. The books were all about British people and British places. Webster wanted books that would mean more to American children. So he wrote three books that used American examples—a grammar book, a spelling book, and a reader. These books were very popular, and millions of them were sold.Webster was interested in changing the spellings of words. He wanted words to be spelled the way they were pronounced. F下列DNA双螺旋结构模型中，各材料之间的连接正确的是(　　)