“牢固地”的英语可以翻译为：hard ...

这房子是用粗木板牢固地建造的.The house was built solidly of rough wooden planks.把碎片牢固地粘在一起.Glue the pieces firmly together.这家公司已在商界牢固地确立了自己的地位.The company established itself firmly in business....