?难以断言
... go without saying 不言而喻(理所当然... there is no saying 难以断言(很难说)... as the saying is 俗话说 ...
英汉双解词典包含3185865条英汉词条,基本涵盖了全部常用单词的翻译及用法,是英语学习的有利工具。