<p>是 in the first context is only used to say:</p>
<blockquote>
<p>Noun1 是 Noun2</p>
</blockquote>
<p>You never say 我是很好, because 好 isn't a noun. You can say</p>
<blockquote>
<p>我是美国人</p>
<p>他是男孩子</p>
<p>我是李红</p>
</blockquote>
<p>because all those relate one noun to another. In the case of 我25岁了, 25 years old isn't a noun, it's a state, and so we don't use 是.</p>
<p>For a simple summary, 是 only relates 2 nouns to each other. If it's not a noun, don't use 是.</p>
<p>You can find more info and examples <a href="http://resources.allsetlearning.com/chinese/grammar/ASGUN7RX#Structure" rel="noreferrer">here</a>, which I find is a good site for beginners to learn chinese, and gives lots of examples to help you understand.</p>

CC BY-SA 3.0
2015-08-16T00:08:37.237Z
是 can also be used as "yes", which is a slightly different usage. You also here this usage in "是吗?", or phrases that use it.
sqrtbottle
CC BY-SA 3.0
2015-08-16T02:32:10.760Z
Can I just ask, in '在小说兴旺的时候，这些媒介是没有的‘ ’没有的‘ is a noun??
Pedroski
CC BY-SA 3.0
2015-08-16T06:59:41.393Z
@Pedroski that is another construct (…是…的), which is often used to emphasise.
Léo Lam
CC BY-SA 3.0
2015-08-17T13:59:11.130Z
@Pedroski The noun is omitted after the 的 since it`s retrieved by the context.
Enrico Brasil
CC BY-SA 3.0
2015-08-17T22:50:01.163Z
I was thinking that. So it is actually noun 是 noun, but the second noun has a stand in, the adjective, in my case above '没有的媒介‘。 Would you agree?
Pedroski
CC BY-SA 3.0
2015-08-16T00:07:21.893Z
2015-08-16T00:07:21.893Z
2020-06-17T09:50:11.587Z
sqrtbottle
<p>There are cases in which "to be" is translated with 是 ( shì ), while in some other cases it seems not to be translated at all.
When should 是 ( shì ) be used? When omitted?</p>

<p>Here some examples:
我很好
wo hen hao 
 I am very well</p>

<p>我是英国人
wǒ-shì-yīng-guó-rén
I am English</p>

<p>Wo hen kuai le
我 很快乐
I'm happy</p>

<p>我 25 岁 了
Wǒ èrshíwǔ suì le
I'm 25 years old</p>

<p>Disambiguation 1: I landed in a similar question: <a href="https://chinese.stackexchange.com/q/10492/11269">When should I use the 是...的 construction?</a> 
Note that it addresses the usage of 是 and的 !</p>

<p>Disambiguation 2: This question has been marked as oossible duplicate of: <a href="https://chinese.stackexchange.com/q/6726/11269">Why is (是) shi4 dropped in this sentence：&quot;我很好&quot;?</a></p>

<p>Indeed the subject is similar. I think that this question is more General, while the other targets a specific case (I was not able to find it before posting my question!). To be noted that some answers are quite similar.</p>

CC BY-SA 3.0
2015-08-16T00:51:09.100Z
possible duplicate of [Why is (是) shi4 dropped in this sentence："我很好"?](http://chinese.stackexchange.com/questions/6726/why-is-%e6%98%af-shi4-dropped-in-this-sentence-%e6%88%91%e5%be%88%e5%a5%bd)
Claw
CC BY-SA 3.0
2015-08-16T02:39:28.190Z
You never use `是` before an adjective as Chinese adjectives are also verbs so "good" also means "to be good". Often `很` seems to take the place of "to be" before an adjective though. I don't know if there are other words besides `很` that can do this or how and why and when it works and doesn't work.
hippietrail
<grammar>
When "to be" should be used? When omitted?
# When "to be" should be used? When omitted?

(Asked by: username_0 on 2015-08-15)

There are cases in which "to be" is translated with 是 ( shì ), while in some other cases it seems not to be translated at all.
When should 是 ( shì ) be used? When omitted?

Here some examples:
我很好
wo hen hao
I am very well

我是英国人
wǒ-shì-yīng-guó-rén
I am English

Wo hen kuai le
我 很快乐
I'm happy

我 25 岁 了
Wǒ èrshíwǔ suì le
I'm 25 years old

Disambiguation 1: I landed in a similar question: [When should I use the 是...的 construction?](https://chinese.stackexchange.com/q/10492/11269)
Note that it addresses the usage of 是 and的 !

Disambiguation 2: This question has been marked as oossible duplicate of: [Why is (是) shi4 dropped in this sentence："我很好"?](https://chinese.stackexchange.com/q/6726/11269)

Indeed the subject is similar. I think that this question is more General, while the other targets a specific case (I was not able to find it before posting my question!). To be noted that some answers are quite similar.

**Tags:** grammar
> **Comments:**
> **username_1**: possible duplicate of [Why is (是) shi4 dropped in this sentence："我很好"?](http://chinese.stackexchange.com/questions/6726/why-is-%e6%98%af-shi4-dropped-in-this-sentence-%e6%88%91%e5%be%88%e5%a5%bd)  
> **username_2**: You never use `是` before an adjective as Chinese adjectives are also verbs so "good" also means "to be good". Often `很` seems to take the place of "to be" before an adjective though. I don't know if there are other words besides `很` that can do this or how and why and when it works and doesn't work.  

---

## 1 answers

### Answer by username_3 on 2015-08-16. Score: 7 | Accepted answer

是 in the first context is only used to say:

> Noun1 是 Noun2

You never say 我是很好, because 好 isn't a noun. You can say

> 我是美国人
>
> 他是男孩子
>
> 我是李红

because all those relate one noun to another. In the case of 我25岁了, 25 years old isn't a noun, it's a state, and so we don't use 是.

For a simple summary, 是 only relates 2 nouns to each other. If it's not a noun, don't use 是.

You can find more info and examples [here](http://resources.allsetlearning.com/chinese/grammar/ASGUN7RX#Structure), which I find is a good site for beginners to learn chinese, and gives lots of examples to help you understand.

> **Comments:**
> **username_3**: 是 can also be used as "yes", which is a slightly different usage. You also here this usage in "是吗?", or phrases that use it.  
> **username_4**: Can I just ask, in '在小说兴旺的时候，这些媒介是没有的‘ ’没有的‘ is a noun??  
> **username_5**: @Pedroski that is another construct (…是…的), which is often used to emphasise.  
> **username_6**: @Pedroski The noun is omitted after the 的 since it`s retrieved by the context.  
> **username_4**: I was thinking that. So it is actually noun 是 noun, but the second noun has a stand in, the adjective, in my case above '没有的媒介‘。 Would you agree?  

---

