the usage of "に" and "を" in the sentence the original sentence is "中国（）旅行する人はおおぜいいます” .Then I think it maybe is the meaning "there are many peoples travel to China",because i think maybe the word has the same meaning to "to" , I filled the blank with "に".But when I check out the answer, it was "を" . Why use "を" instead of "に" ??