work force的用法和样例：
例句
- Half of its work force is employed in agriculture.
半数劳动力从事农业工作。 - The farm labour force is running down steadily.
农场里的劳动力在不断减少。 - The work force is growing with the influx of youngsters.
随着年轻人的投入，劳动大军正在发展壮大。 - A number of women are now leaving the work force to become full-time homemakers.
许多妈妈正离开劳动大军，回家做个全职母亲。
