题目

How many words one uses cannot be measured (测量)exactly. However, Professor Seashore concluded the first- graders entered school with at least 24,000 words and add 5,000 each year so that they leave high school with at least 80,000. These figures( 数字) are for recognition vocabulary （词汇），the words we understand when we read or hear them, which are more than our active( 活跃的) vocabulary, the words we use in speaking and writing.     Using the words you recognize in reading will help get them into your active vocabulary. In your reading, pay attention to these wor宇航员长时间在太空飞行，身体失重影响血液向下肢的运输，如果不采取适当的措施，就会造成下肢肌肉缺乏营养，甚至萎缩．为了解决以上问题，科学家利用仿生学原理设计出奇特的宇航服（又叫“抗荷服”），使宇航员在失重状态下，也能使体内的血液运输到离心脏较远的下肢．科学家模仿的生物是（ ）A．骆驼B．驼鸟C．长颈鹿D．大象