题目

The computer keyboard helped kill shorthand---a system of rapid handwriting, and now it's threatening to finish off handwriting as a whole. When handwritten essays were introduced on the SAT exams for the class of 2011, just 15% of the most 1.5 million students wrote their answers in cursive (草写字母）.The rest? Block letters. And those college hopefuls are just the first edge of a wave of US students who no longer get much handwriting instructions in the primary grades, frequently 10 minutes a day or less. As a result, more and more students struggle to read and write cursive. At在等差数列项的和等于 （ ）A． B． C． D．