To parse a sentence, you must analyze each of its component parts, examining the nature of its clauses, the parts of speech and grammatical functions of it words, and the relationships between its words.
The sentence “When I married my wife, she was a teacher, but she later became an accountant after she took a degree course in accounting” is a compound-complex sentence because it has two independent and two dependent clauses. A compound-complex sentence must have at least two independent clauses and at least one dependent clause. The independent clauses can stand alone: “she was a teacher” and “she later became an accountant.” The dependent (or subordinate) clauses cannot stand by themselves but begin with subordinating conjunctions: “When I married my wife” and “after she took a degree course in accounting.” So the clause pattern for the sentence is dependent, independent, independent, dependent (D, I, I, D).
Now let's look at each of these clauses. We'll start with the first dependent clause: “When I married my wife.” “When” is a subordinating conjunction that tells us we have a dependent clause. The subject is the pronoun “I.” The verb is “married” (past tense in this case). The direct object is the noun “wife,” which is modified by the possessive pronoun “my.”
The sentence's first independent clause is “she was a teacher.” Its subject is the pronoun “she,” and its verb is the third person singular past tense of the copula, namely, “was.” The predicate complement (which describes the subject) is the noun “teacher,” which is accompanied by the indefinite article “a.”
The coordinating conjunction “but,” links the second independent clause, “she later became an accountant.” The pronoun “she” again serves as the subject with “became” as the verb (past tense), which is modified by the adverb “later.” The noun phrase “an accountant” (indefinite article plus noun) follows, with “accountant” as the direct object.
Finally, we have the last independent clause “after she took a degree course in accounting.” It begins with the subordinating conjunction “after” and once again features the pronoun “she” as the subject. The verb is “took” (past tense), and it is followed by the direct object “course,” which is part of the noun phrase “a degree course” and is modified by the indefinite article “a” and the adjective “degree.” The clauses ends with a prepositional phrase made up of the preposition “in” and the noun “accounting.”