needless to say 意思是：as is self-evident or to be expected
也就是：很显然,毋庸置疑,不用说.
与它可以替换的词语或短语有：
undoubtedly,unquestionably,without doubt,obviously
或者也可以这样说：
It's needless to say that,(宾语从句)
就相当于：
It's clearly that,……
Needless to say,learning without thinking is useless.
不用说,学而不思则罔.
Needless to say,I agree with you.
不用说,我赞同你.
Needless to say,he never came again.
很明显,他再也没有来.