The methods of spectrum analysis vary according to the wavelength region were studied.
  • 1、
【正确答案】 1、正确答案：were一去掉were    
【答案解析】解析：考查过去分词。过去分词studied作后置定语修饰region，其作用相当于定语从句省去which／that及系动词。此句系动词用错，应该是was才对，所以不能直接加which／that，而是把were删掉。