要求 (yāo qiú) functions as both a verb (to require or demand) and a noun (a requirement or demand). As a verb it takes a subject and the pattern 要求 + someone + to do something (老师要求学生认真, the teacher requires students to be serious). As a noun it describes conditions or standards that must be met (达到要求, to meet requirements). It is stronger than 请求 (qǐng qiú, to request politely) and implies an expected or mandatory compliance.