区别用 that 还是用 what 来引导从句，最简单的方法如下：

▲that 引导从句时不充当句子成分（定语从句除外），what 引导从句要充当句子成分（比如主语、宾语等）。如：

1. We believe that he is honest. 我们相信他是诚实的。（that 在此不充当句子成分）

2. We believe what he said. 我们相信他说的话。（what在从句中用作动词said的宾语）

3. I think that I did the right thing. 我认为我做对了。（that 在此不充当句子成分）

4. I think what I did was right. 我认为我做的是对的。（what在从句中用作动词did的宾语）

▲在通常情况下，介词（except, but, in等少数介词除外）后面可以接 what 引导的从句，但不能接 that 引导的从句，所以下面句子中的 what 均不可换成 that，因为它们所引导的从句是用作介词的宾语：

1. He always stands for what is right. 对于正确的东西他总是支持的。

2. I’ll pay you back for what you did to me. 你对我做的那些事我要进行报复。

3. The company is ready to take the blame for what had happened. 公司准备对已发生的事情承担责任。

4. She felt glad at what he had said. 听到他的话她感到很高兴。

5. There are limitations on what we can spend on this tax year. 在这个税收年度里我们可以开销的项目有限。

6. A good student must connect what he reads with what he sees around him. 一个好学生必须将他所读到的东西与他周围所看到的东西联系起来。

7. He’s too particular over what he eats and drinks. 他对吃喝太挑剔。

8. He called our attention to what he said. 他提醒我们注意他说的话。

你的句子翻译以及相关句举例：

It is the same old story of not being grateful for what we have until we lose it.

人们总是这样——拥有时不珍惜，失去时才婉惜。

说明：句中的 It is the same old story 是英语中的惯用句式，意思是：一直都是这样；又是老样子；又是那老一套；还是老生常谈的事。多用于表示糟糕的情况以前多次出现。又如：

1. It’s the same old story. They want one person to do three people’s jobs. 又是老一套。他们想让 1 个人做 3 个人的工作。

2.  It’s the same old story—the rich get richer and the poor get poorer. 还是老样子——富人愈富，穷人愈穷。

3. He says we haven’t got enough money to go on holiday. It’s the same old story every year.  他说我们没有足够的钱去度假，每年都是老一套说辞。

4.  It’s the same old story of a badly managed project with inadequate funding. 又是一桩资金短缺、经营不善的老故事。

5.  It's the same old story—too much work and not enough time. 情况还是跟过去一样——工作太多，时间不够。

6.  It’s the same old story—everybody wants the house tidy, but nobody wants to tidy it himself.  还是老生常谈的事——谁都想让房子整洁，可谁也不愿意亲自整理。