"他们坚定的认为" 在英语中可以翻译为 "they are firmly convinced that"。
这个短语是由 "firmly" 和 "convinced" 两个单词组合而成。"Firmly" 意思是 "坚定地"，"convinced" 意思是 "确信"。
下面是一些例句：
They are firmly convinced that the earth is flat. 他们坚信地球是平的。
She is firmly convinced that she can achieve her goals. 她坚信她能达到自己的目标。
He is firmly convinced that he is always right. 他坚信自己总是对的。
这个短语是由 "firmly" 和 "convinced" 两个单词组合而成。"Firmly" 意思是 "坚定地"，"convinced" 意思是 "确信"。
下面是一些例句：
They are firmly convinced that the earth is flat. 他们坚信地球是平的。
She is firmly convinced that she can achieve her goals. 她坚信她能达到自己的目标。
He is firmly convinced that he is always right. 他坚信自己总是对的。