A-A+
Their factory has developed a kind of ______to
问题详情
Their factory has developed a kind of ______to help people walk.
A．the machine
B．machines
C．machine请帮忙给出正确答案和分析，谢谢！
参考答案
正确答案：C
解析：句意:他们工厂已经研发出了一种可以辅助人行走的机器。 本题考查的是短语a kind of，后面的名词用单数，名词前不加冠词。
