Engineering is challenging course of study that requires thoroughunderstanding of mathematics and science.
A. the; a
B. a; the
C. 不填；不填
D. a; a
网友回答
A. the; a
B. a; the
C. 不填；不填
(答案→)D. a; a
解析：考查冠词的用法区别。第一空course是课程，前面有challenging修饰，故表示泛指；第二空表示对某物的理解，understanding前加a,故D正确。