谁能跟我讲解下这个英语题?这个是2011年12月的四级考试的完型填空的一段
Nearlyhalfoftheorganizationstoldresearcherstheywerealreadystrugglingtofind68Dwithskillsinscience,technology,engineeringandmaths(STEM).69Aevenmorecompaniesexpecttoexperience70BofemployeeswithSTEMskillsinthenextthreeyears.
68.A)audienceC)partners
B)officialsD)staff
69.A)whileC)for
B)becauseD)although
70.A)exitsC)absences
B)shortagesD)departures
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为什么70题选shortage啊?怎么感觉翻译起来不对劲啊?