為什麼這句英文有兩個動詞？ 我是初學者，幫幫我。?

As he yawned, his nose went up in the air and he smelled something.
當他打哈欠, 他的鼻子抬起朝向空中 而且 聞到一些什麼味兒。

Sentence structure: a compound-complex sentence, containing two independent clauses 獨立子句 and one dependent clause 從屬子句; there are 3 finite verbs all together.

independent clause 1: his nose went up in the air (verb = went)
coordinating conjunction 並列連詞: and
independent clause 2: he smelled something (verb = smelled)

dependent clause: As he yawned, (verb = yawned)
*** this is an adverb clause introduced by the subordinating conjunction 從屬連詞 "as"
*** comma is compulsory

*** there must be one and only one finite (限定的) verb in each of the clauses

As he yawned his nose went up in the air and he smelled something.
他抬起鼻子/ 抬起頭 打了個哈欠, 而且 聞到一些什麼味兒。

《 As he yawned his nose went up 》後動詞 是 “配搭介詞短語” 的用法, 作 補充形容前一動作。

另例: Just to “try” as you “may fail”, you will win with another try.
儘管去嘗試吧 即使你可能會失敗, 再另一次的嘗試 你一定會成功的。（ 不對喔！不一樣的狀況, 只供參考吧～????）

《 yawn 原動詞 ☞ yawned 過去式 》

有and所以是兩句話