有一不纯的硫酸铵样品（杂质中不含氮元素），经分析知道其中含氮的质量分数为18.9%，则样品中含（NH₄）₂SO₄的质量分数为______．

Jobs are hard to get and, ________， more young people are continuing their education.[ ]

A. above all  

B. as a result

C. after all  

D. on the contrary