题目选项分析

Nearly all employees of the factory who have completed their high school diploma have earned their factory safety certificate, having easily completed the eight week training course. The high school graduates who haven't earned the certificate are ones who have evening obligations that have prevented them from taking the course. Overall, though, most of the factory workers have not earned the certificate.

If the statements above are true, which one of the following also must be true?

【选项】A large proportion of the factory workers have not graduated from high school.