It is estimated that the number of basic words known by English-speaking school children of age s______ is around 7800, counting word stems and their inflectional derivatives as single words
【正确答案】：six(P263)解析:据估计,大约6岁的说英语的学龄儿童的基本词汇量,如果把词干和屈折派生词都算作独立的单词加以计算的话,大约要有7800个左右
