是的，the加单数可数名词可以表示一类人或事物
例如：The horse is a useful animal.马是一种有用的动物.
名词复数也可表示一类人或事物，例如：Horses is a useful animal.
所以复数前不一定都要加定冠词.
如果复数名词中表示泛指意义，则其前通常不用定冠词（当然原则上也不会用不定冠词，因为是复数名词嘛）。
如：
Trees drop their leaves in autumn. ；树木在秋季落叶。
Books may not be taken out of the library. ；图书馆的图书不得携出馆外。
Students may not use the staff car park. ；学生禁用职工停车场。
People are becoming less tolerant of smoking these days. ；如今人们对吸烟较为难以容忍了。
Women now make up two-fifths of the British labour force. ；妇女构成英国劳动力的五分之二。
但是，如果复数名词是表特指，意义，则应在其前用定冠词。如：
The books sold out in a week. ；书在一周内就售完了。
The apples were ripe enough to pick. ；苹果够熟了，可以摘了。
Hurry up! The guests will be arriving at any minute! ；快! ；客人就要来了!
The children seemed to be awake when I went into their room. ；在我进屋时，孩子们似乎醒了
