英语文法: 复合句(Complex Sentence) 分析
Source: Zhihu
(prepared by: alexcwlin; edited by: Adam Lam)

Question:
你好，请问可以帮我分析一下这个句子吗。
As he spoke, so lightly, tapping the end of his cigarette against the ashtray, she felt the strange beast that had slumbered so long within her bosom stir, stretch itself, yawn, prick up its ears, and suddenly bound to its feet, and fix its longing, hungry stare upon those far away places.

alexcwlin comments:
This is an excerpt from the book “The Collected Stories of Katherine Mansfield” by Katherine Mansfield.

It is a complex sentence (复合句) which is made up of 1 Main Clause (主句) and 2 Dependent Clauses (从属句).

Dependent Clause #1: “As he spoke, so lightly, tapping the end of his cigarette against the ashtray,” Main Clause: “she felt the strange beast” Dependent Clause #2: “that had slumbered so long within her bosom stir, stretch itself, yawn, prick up its ears, and suddenly bound to its feet, and fix its longing, hungry stare upon those far away places.”

A.    Main Clause
“she felt the strange beast”
Subject: “she” (Pronoun)
Verb: “felt” (Transitive Verb, Simple Past Tense)
Object: “the strange beast” (Noun Phase, Object of “felt”)

B.    Dependent Clause #1
“As he spoke, so lightly, tapping the end of his cigarette against the ashtray,”
Connector: “as” (Subordinating Conjunction linking the Dependent Clause to the Main Clause)
Subject: “he” (Pronoun)
Verb: “spoke” (Intransitive Verb, Simple Past Tense)
Modifiers:
#1: “so lightly” (Adverbial Phrase, modifying Verb “spoke”)
#2: “tapping the end of his cigarette against the ashtray” (Adjectival Phrase, modifying Subject “he”)

Dependent Clause #2
“that had slumbered so long within her bosom stir, stretch itself, yawn, prick up its ears, and suddenly bound to its feet, and fix its longing, hungry stare upon those far away places.”
Connector: “that” (Relative Pronoun, linking the Dependent Clause to the Main Clause, also Subject)
Subject: “that” (Relative Pronoun, which serves the dual roles of a Connector and also the Subject in representing “the strange beast”)
Verb: “slumbered” (Intransitive Verb, Simple Past Tense)
Modifiers:
#1: “so long within her bosom” (Adverbial Phrase, modifying “slumbered”)
#2: “stir” (Bare Infinitive, modifying Subject “that”, Noted 1)
#3: “stretch itself” (Bare Infinitive Phrase, modifying Subject “that”, Noted 1)

#4: “yawn” (Bare Infinitive, modifying Subject “that”, Noted 1)
#5: “prick up its ears” (Bare Infinitive Phrase, modifying Subject “that”, Noted 1)

#6: “and suddenly bound to its feet” (Bare Infinitive Phrase, modifying Subject “that”, Noted 1)

#7: “and fix its longing, hungry stare upon those far away places” (Bare Infinitive Phrase, modifying Subject “that”, Noted 1)

Note 1: A Bare Infinitive can follow the Verb “had” as a Verb of “causation”;
See: https://www.myenglishpages.com/site_php_files/grammar-lesson-infinitive.php#:~:text=The bare infinitive is also,let/had him do it.&text=The verb help is followed by the bare infinitive
However, it needs an Object following “had”, and so my guess is the Pronoun “itself” is understood.