To hold water 按字面解释当然可以说是“不让水漏出来”。但是，它的另外一个意思是指某一个人找的借口、提出的理由、或说的话是确实的，站得住脚的。美国人经常说："That excuse simply doesn't hold water."意思是：那个借口根本站不住脚。我们来举个例子：

"The accused man claimed that he'd been in another city the night of the murder. But his story didn't hold water after three different witnesses testified in court that they had seen him running from the scene of the crime."
这句话的意思是：“这个被控告的人说，发生谋杀案的那天晚上他出门去了，不在当地。但是，有三个不同的证人都出庭作证说，他们看见他从作案的地点逃跑。因此，他说出事那天他不在当地的说法根本是靠不住的。”

in point of fact
事实上，实际上
He said he would pay, but in point of fact he has no money.
他说他要给钱，可事实上他没有钱。