21。Most teen-agers who work for pay hold jobs that require few skills, little responsibility, and also no hope for career advancement. (A) little responsibility, and also (B) little responsibility, and with (C) little responsibility, and offer (D) carry little responsibility, and (E) carry little responsibility, and offer
我个人认为这个句子 job that require few skills, carry little responsibility, and offer no hope for career advancement.实际上是三个对称的结构,三个动词require, carry, offer分别是修饰三个名词skill, responsibility, career advancement, 所以这个carry不能少。