问题
About ________ of the workers in the factory were born in the ________.
A:two-thirds, 1970
B:two-thirds, 1970s
C:two-third,1970
D:two-third, 1970s
B:two-thirds, 1970s
C:two-third,1970
D:two-third, 1970s
正确答案是：
