known to us, increasing number of students are buried in their studies.
A. What is;a
B. It is;the
C. As it is;the
D. As is;an
网友回答
A. What is;a
B. It is;the
C. As it is;the
(答案→)D. As is;an
解析：本题考查定语从句和冠词。“，”前后都是句子，可判断第一个空应用连词，排除B项； a number of +复数名词+复数谓语动词；而the number of +复数名词+单数谓语动词；再结合are及increasing可知第二个空应填an。句意：众所周知，专心学习的孩子越来越多。