这些产品是按低标准制造的，所以经常很快坏掉。

These products are made with ___low standards, so they often break quickly.

老实说，我对他的专业技能评价很低。

Honestly, I have a very ___low opinion of his professional skills.

污染导致许多工业城市的生活质量低下。

Pollution contributes to the ___low quality of life in many industrial cities.