both come in adult and children’s version这里的version为何不需要复数形式

原句：The test comes primarily in twoforms: the Stanford-Binet Intelligence Scale and the Wechsler IntelligenceScales .

来自2007考研英语一text2第三段第二句话。

both come in adult and children’s version = bothcome in adult verrsion and children's version 这是蒙后省略。