directly y proportional to成正比
directly proportional function正比例函数
be directly proportional成正比
vary directly proportional to和
directly proportional to正比于;与……成正比;成正比
Be directly proportional to成正比;成正比例;正比于;与
directly proportional detail正比例的
directly proportional to the amount数量成正比
directly proportional burning velocity law燃速正比定律