问题补充：
－How many workers are there in your factory?
－ the workers in my factory over two thousand .
A. The number of , is
B. The number of , are
C. A number of, is
D. A number of , are
答案：
(答案→)A. The number of , is
B. The number of , are
C. A number of, is
D. A number of , are
解析：表示···的数量用the number of，且作为主语时，相当于单数形式，故选答案为A
