regretful

感到遗憾的

①用作表语时可接that从句。

【例】We are regretful that we are unable to supply the entire quantity required.

很遗憾，我方不能按照所需数量全部供应。

②用作表语时也可接用不定式。

【例】We feel regretful to learn of your inability to consider our counter bid against your offer for engines.

得悉你方不能考虑我方对你方发动机报盘的还盘，感到遗憾。

regretfully

感到遗憾地

【例】Should the delay be longer than two weeks, we shall regretfully have to cancel the order.

如果延误超过两个星期，很遗憾我们就不得不取消此订货。

regrettable

令人感到遗憾的

用作表语或补语。

【例】It is very regrettable that we failed to make a careful study of the payment problem before we signed the contract.

非常遗憾，在签订合同之前，我们对付款问题没有慎重研究。