请问这个句子是用单数还是复数?
Each of the 500 students have /has a computer.
Since the 1920's aircraft manufacturers have tried to build airplanes with frictionless wings , shaped so smoothly and perfectly.(这个选项不是正确答案)
请问这句话的shaped引导的句子是修饰句子的主语aircraft manufacturers 还是修饰它前面的wings?