More and more people using mobile phone and computer to instead o_英语解答

More and more people using mobile phone and computer to instead of letters.
这句话的mobile phone and computer 后面要加S

人气：227 ℃　时间：2019-09-25 08:38:45

解答

不用,指代一类.可是letter加个s干什么呢?加the,特指一类事物.