试题题干
Fill in each of the following blanks with a word or an expression.
Two types of symbols may be identified: 
and auditory symbols.
参考答案
试题解析
可以识别两种类型的符号：视觉符号和听觉符号。
Fill in each of the following blanks with a word or an expression.
Two types of symbols may be identified: and auditory symbols.
可以识别两种类型的符号：视觉符号和听觉符号。