单选题
One of the properties of light is（ ）traveling in wave form as it goes from one place to another.
Ait
Bit’s
Cits
Dtheir
正确答案
答案解析
该题考查非谓语动词。句中traveling为动名词做表语，空格处所填内容做动名词的逻辑主语，首先排除B，D选项，能做动名词逻辑主语的词有形容词性物主代词，名词所有格或人称代词宾格，故答案为C。