not as beautiful as
彼女は姉さんほど美しくない。
She isn't as beautiful as her older sister.
彼女は姉ほど美しくない。
彼女はお母さんほど美しくない。
She isn't as beautiful as her mother.
彼女は、メアリーより賢い、しかしメアリーほど美しくない。
She is smarter than Mary, but not as beautiful as Mary.