单选题 Why is scientific training becoming less attractive to U. S. students?

A、 Because the U. S. students are unwilling to face the competitions between them and foreign students.
B、 Because it is not so rewarding in this career path as before due to the increasing amount of students.
C、 Because foreign students take up good position in this field for their advantage.
D、 Because U. S. students do not think scientific training can help them make a lot of money.

【正确答案】 B

【答案解析】文章第二段第一句谈到了美国学生对于学习科学领域的学科并接受相应培训不太感兴趣了，因为随着外国留学生的进入，生源的激增，在这些领域继续做下去所获得收益已经减少了。[A]和[D]文章未提及。[C]与文意不符，文中提到优秀的美国学生并不想从事对于来自较贫穷国家的学生很有吸引力的研究助理之类的工作，他们想做其他领域中更好的。