Linguists can concentrate on all the aspects of language at once.

正确答案： 错误
答案分析： 语言是一种包含有多层次和多方面的综合体，语言学家们不可能一下子都能够研究得面面俱到，每一次只能集中研究其中的一个方面。 改正：Linguists have to concentrate on one aspect of language at a time since language is a complicated entity with multiple layers and facets. 22.In classifying the English consonants and vowels, the same criteria can be applied.