To talk with your parents like that is impolite.（写出同义句）

实际上,老师让你练习形式主语“It”的用法。（It's）（impolite）(to) (talk) with your parents like that。原句中“To talk with your parents like that ”作主语,is为系动词,impolite是表语。再举一例：It's important to learn English well。= To learn English well is important。