AP Music Theory Complete Based on Cues is the skill category where you finish a piece of music using the information you are given. You take a cue like a figured bass line, a Roman numeral analysis, or a melody, and you build out the missing parts while following 18th-century stylistic norms. This is the writing and composing side of the course, and it shows up in the part-writing and harmonization free-response questions.

In short: you are handed part of a four-voice texture, and your job is to complete it correctly. That means spelling chords accurately, connecting them with good voice leading, and labeling harmony with Roman and Arabic numerals.

What Complete Based on Cues Means

The official grouping description is simple: complete music based on cues, following 18th-century stylistic norms. The "cues" are the starting materials the question gives you.

You might receive any of these:

A figured bass line with numbers under the bass notes
A Roman numeral analysis with no notes filled in yet
A given melody that needs harmony underneath it

Your task is to add the missing voices, choose appropriate chords, and keep the four parts moving according to common-practice voice-leading conventions. Think of it as reverse-engineering a Bach-style chorale from a set of hints.

What This Skill Requires

To complete music based on cues, you need fluency with the building blocks from earlier units. This skill pulls everything together.

You should be comfortable with:

Chord spelling for triads and seventh chords in major and minor keys
Roman numeral and figured bass symbols, including inversions
SATB spacing, doubling, and range conventions
Voice-leading rules like resolving tendency tones, avoiding parallel fifths and octaves, and handling the leading tone
Cadence types and how phrases close

The 18th-century style is the reference point. Your goal is music that sounds like a smooth four-voice chorale, not just technically correct chords stacked in isolation.

Subskills You Need

The CED breaks this category into four subskills.

4.A: Spell chords and connect them with 18th-century voice leading This is the foundation. You apply knowledge of common-practice tonality to spell each chord correctly and then move from one chord to the next using proper voice leading. Every other subskill depends on this one.

4.B: Realize a figured bass and analyze it You are given a bass line with figures. You add the soprano, alto, and tenor to match the figures, then provide a Roman numeral analysis of the completed progression. The figures tell you the intervals above the bass and the inversions.

4.C: Complete a progression from a Roman numeral analysis Here the Roman numerals are already written. You build the full four-voice progression that matches them. You decide voicing, doubling, and voice leading while staying faithful to the given harmonies.

4.D: Compose a bass line to harmonize a melody You start with a given melody and write a bass line that implies appropriate harmony. Then you identify that implied harmony using Roman and Arabic numerals. This subskill tests whether you can hear and choose chords that fit a melody.

How It Shows Up on the AP Exam

This skill category is assessed only in the free-response section, not in multiple choice. According to the CED, each subskill maps to a specific FRQ type.

Subskill	Task	Where it appears
4.A	Spell and connect chords	Foundation for FRQ 5, 6, 7
4.B	Realize figured bass, add Roman numerals	FRQ 5 (part writing from figured bass)
4.C	Complete from Roman numerals	FRQ 6 (part writing from Roman numerals)
4.D	Compose a bass line to harmonize a melody	FRQ 7 (composing a bass line)

The free-response section is worth 45% of the exam and runs about 70 minutes total, with part writing and composition grouped in one timed block. Since this category never appears in multiple choice, the only way to earn these points is to write clean, complete music under time pressure.

Examples Across the Course

This skill draws on concepts from many units, which is part of why it sits at the end of the framework.

From Triads and Seventh Chords: You spell a V7 in root position and place its chord tones across four voices, making sure the leading tone and seventh are present. This relies on chord-quality and figured-bass knowledge from the fundamentals units.
From Harmony and Voice Leading I: You realize a figured bass that includes a 6 under a bass note, meaning a first-inversion triad, and you double the correct tone while avoiding parallels with the bass.
From Predominant Function: A Roman numeral line gives you I then ii6 then V then I. You complete the predominant-to-dominant motion and resolve the cadence correctly.
From Embellishments: A given melody includes a passing tone between two chord tones. When you write the bass line, you recognize that the passing tone is not a new chord, so you keep the same harmony underneath it.
From Secondary Function: A figured bass with a raised pitch signals a secondary dominant like V/V. You spell it with the correct accidental and resolve its tendency tones into the next chord.

How to Practice Complete Based on Cues

These are practical study suggestions, not official rules.

Drill chord spelling until it is automatic. You cannot afford to slow down to figure out the notes of a vii°6 during the exam.
Practice all three cue types separately: figured bass realization, Roman numeral realization, and melody harmonization.
Check every chord connection for parallel fifths and octaves before moving on. Build the habit so it becomes second nature.
Always resolve the leading tone up to tonic, especially in outer voices and at cadences.
For melody harmonization, sing or play the melody first and listen for where the harmony naturally wants to change.
After finishing a progression, write or double-check the Roman numerals. For 4.B you must supply the analysis, so practice labeling as you go.
Time yourself. Completing accurate part writing quickly matters because this is a timed block.

Common Mistakes

Writing parallel fifths or octaves between any two voices, which is one of the most penalized errors in 18th-century style.
Forgetting to resolve the leading tone, or doubling it.
Misreading figured bass numbers and choosing the wrong inversion.
Spacing voices too far apart between soprano, alto, and tenor.
Doubling the wrong chord member, such as doubling the third of a major triad or the leading tone.
For 4.D, choosing harmony that clashes with the melody notes or changing chords on embellishing tones that should stay over one chord.
Leaving out the Roman numeral analysis on the figured-bass question when it is required.
Spelling chords with the wrong accidentals for the key, especially in minor and with secondary function.

Quick Review

Complete Based on Cues means finishing four-voice music from a given cue using 18th-century norms.
It appears only in the free-response section, in the part-writing and composition questions.
4.A is chord spelling plus voice leading, the base for everything else.
4.B realizes figured bass and adds Roman numerals.
4.C completes a progression from given Roman numerals.
4.D composes a bass line to harmonize a melody and labels the implied harmony.
The biggest payoff comes from automatic chord spelling, clean voice leading, and accurate analysis labels.