The number of foreign students attending Chinese universities rising steadily since1990.
A. is
B. are
C. has been
D. have been
网友回答
A. is
B. are
(答案→)C. has been
D. have been
解析：句意：上中国的大学的外国学生的数量自从1990年以来一直稳步上升。根据since1990和句意判断用现在完成时表示状态一直持续，the number是数字，做主语时谓语用单数形式。结合句意可知，选C。
考点: 考查时态和主谓一致的用法。