问题补充：
people went to the concert that was held in Reming Square the night of May 25.
A. Two thousands, on
B. Many thousand, in
C. Thousands of, on
D. Several thousands of, in
答案：
A. Two thousands, on
B. Many thousand, in
(答案→)C. Thousands of, on
D. Several thousands of, in
解析：英语中数词表示概数时，后面加s，和介词of搭配使用。用原形时表示具体数字和数词搭配使用。句意:在五月二十五日的晚上成千上万的人去听在人民广场上举行的音乐会.在表示时间时,on表示在具体的某一他,in表示在一个时间范围,结合语境可知选C.
