那个时候Beijing不缺乏高中师资，low high school enrollment was due to policy,

没有招工的机会吧？ 

there were vocational schools with guranteed positions in state-owned companies. I went to one (via back-door) and got a position in one of the most technically advanced companies (by then) upon graduation. My work place was air-conditioned in 1975/76 and I could practice English with my foreign co-workers sitting in the same room.

But I still think I would have done much better had I have the opportunity going to high school.