大家知道 What kind of +n? 和 What kind of +a+n? 是有区别的。
What kind of doctor is he? 他是哪一类医生？（内科还是外科医生）
What kind of a doctor is he? 他医术如何？（医术是否高明）
What kind of hospital is it？它是哪一类医院？（内科还是外科医院）
What kind of a hospital is it？这家医院怎么样？（好还是不好）
What kind of job is that? 这是哪一类的工作？
What kind of a job is that? 这算是什么工作？（含义是：你应为这工作感到羞愧）。
He didn't know what kind of a country it is until he came to China.(这个国家怎么样）
What kind of car is it? 和 What kind of a car is it?