The negative structure of 比 should be: Noun A + 不比 + Noun B + adjective OR Noun A + 没有 + Noun B + adjective Examples: 苹果不比菠萝大。píng guǒ bú bǐ bō luó dà | An apple is not as big as a pineapple. 圆珠笔没有钢笔好用。yuán zhū bǐ méi yǒu gāng bǐ hǎo yòng | Ballpoint pens are no better than fountain pens.