The golden rule here is spread your risk.

【翻译】这里的指导原则是：分散你的投资风险。

【分析】首先，可以排除是印刷错误。都多少年了，《新概念英语》不会出现这么低级的失误。

不过，当今社会，有一个不是很好的现象存在于语言中，而且大有发展的趋势。不仅在我们汉语中，而且英语中也时常出现。那就是：标点符号的失却、误用或乱用！实话实说，现在的年轻人，不怎么在乎标点符号了，愿意怎么说就怎么说，愿意怎么写就怎么写，几乎到了随心所欲的地步，标点符号有没有、对不对，都无所谓。君不见：网络发帖、QQ聊天、微信聊天上的语言简直看不懂了。我们50岁以上的人，确实落伍啦！

我认为，这个句子正确的书面语应该是：

1. The golden rule here is to spread your risk. （加to）

2. The golden rule here is: spread your risk.（加冒号）

3. The golden rule here is “spread your risk”.（加引号）

4. The golden rule here is spread your risk.（用黑体）

5. The golden rule here is spread your risk.（用斜体）

6. The golden rule here is spread your risk.（黑体加斜体）

“分散风险”是投资界常用的一个术语。作为一个固定说法，它带有“告诫，警示”的作用，类似祈使句性质。所以，有时用在句中，并非以动词不定式的形式出现。但应该用特殊的标点符号、字体颜色等予以标识。如：2,3,4,5,6。

关于这个话题，我想起以前讨论过的一个问题。

有这样一个句子：He came in without so much as a by your leave. （词典上就是这样写的）

by your leave 是一个比较古老的习语。尽管词典收录了这个词条及其例句，但在现代英语中极少使用，我们一般用permission 取而代之。

众所周知，口语是有语调和停顿的。但是，在书面语中，则要有标点符号。a by your leave 是一个非常不规范的写法，规范的书面语应该是：

a by-your-leave（加连字符）

a “by your leave”（加引号）

a by your leave（黑体）

a by your leave（斜体）

a by your leave（黑体加斜体）

我始终认为：当一个固定的短语（如：介词短语或者动词短语）被用作“名词”时，为了排除这个短语原来的结构、用法和语义，用于句子中，在书写时需要加连字符、引号、黑体或者斜体，甚至黑体斜体连用，以示区别。

下面是我咨询了两个老外后，他们给的答复，现摘录如下。（蓝色是我的问题，红色是老外的回答）

Question One:

Generally, if a fixed phrase is used as a noun, how can we write the noun correctly in a sentence?

【老外】 最好是hyphen 加斜体，其次是hyphen，再其次是斜体。

Question Two:

In English, if a fixed phrase such as a prepositional phrase and a verbal phrase is used as a noun, which of the following are correct written language?

Group One:

1. He came in without so much as a by-your-leave. (hyphenated)

2. He came in without so much as a “by your leave”. (in inverted commas)

3. He came in without so much as a by your leave.(in bold type)

4. He came in without so much as a by your leave. (in italic type)

5. He came in without so much as a by your leave.

Group Two:

1. A forget-me-not is a small plant with tiny blue flowers. (hyphenated)

2. A “forget me not” is a small plant with tiny blue flowers. (in inverted commas)

3. A forget me not is a small plant with tiny blue flowers. (in bold type)

4. A forget me not is a small plant with tiny blue flowers. (in italic type)

5. A forget me not is a small plant with tiny blue flowers.

【老外】I'd choose the hyphenated form in both cases.

Thank you. Do you mean the rest of the sentences are all incorrect?

【老外】I can't say that with certainty, as some writers might prefer one of the other ways. But they would probably get red-lined if I were the editor.