请问我的这个有什么语法错误吗?帮忙改正下,
theprimarystructureofXGcontainspentamericrepeatunitswhichwasformedbytwoD-glucose,twoD-mannoseandoneD-glucuronicacid.
ApproximatelyonehalfoftheterminalsD-mannosecontainapyruvicacidresiduelinkedviaketogrouptothe4and6positions.这个句子有什么语法错误吗?