______ number of people using the internet is on ______ increase

______ number of people using the internet is on ______ increase.
A、the, the
B、the, /
C、a, /
D、a, the
【正确答案】：A
【题目解析】：the number of + 名词复数，为固定用法，指人数。on the increase = increasing 意为不断增长，故选A。