是：am/is/are
Use 是 (shì) to connect two nouns
是 (shì) is used like the English verb “to be” when you want to connect two nouns (or pronouns) together in a sentence to explain what something, or someone, is:
我是David。
他是Mike。
她是Sophie。
们: Plural Suffix
"们（men）" as a plural suffix is only used after Pronouns to mean
multiple people. For example, 我 means "I", 我们means "we".
的: Possessive Particle ('s)
的（de）" is used after a noun to indicate ownership.
For example, 他 means "he", 他的 means "his".
我 I --- 我的老师 my teacher--- 我们的同学 our classmate
他 He--- 他的老师 his teacher --- 他们的同学 their classmate
Sentence Frames
Subject is something.
Subject + 是(shì) + Noun.
我是一个老师。 (I am a teacher.)
她是我们的同学。 (She is our classmate.)
Someone is XX years old.
Subject + Number + 岁(suì)
它一岁。 (It is one year old)
我二十岁。(I am 20 years old)
她十八岁。 (She is 18 years old)
Something is $XX.
Subject + Number + 块(kuài)
它三十四块 （It is thirty four Chinese dollars.）
A Song with a lot of "一个" and "我的"
你存在 you exist (nǐ cún zài)
我深深的脑海里 deeply in my brain/mind (wǒ shēn shēn de nǎo hǎi li)
我的梦里 in my dream (wǒ de mèng li)
我的心里 in my heart (wǒ de xīn li)
我的歌声里 in my songs (wǒ de gē shēng li)