Grade 3 Fall — Personal Narrative, Complex Sentences with Subordinate Clauses, and Morphology with Affixes and Roots
Lesson 3 50 min eng.g3.f.lesson_03.when_because_subordinate_clause_intro

Meet the Subordinate Clause — When, Because, and the Comma Rule

Skills targeted
Objectives
  • Students identify a subordinate clause and the subordinating conjunction that starts it.
  • Students combine two simple sentences into one complex sentence using WHEN or BECAUSE, applying the fronted-vs-back comma rule.
Vocabulary
independent clausesubordinate clausesubordinating conjunctioncomplex sentenceWHENBECAUSEcomma rule

Lesson plan

Warm-up

5 min

Sentence-pair detective: teacher writes two short sentences on board ('The bell rang. We hurried inside.') and asks: 'How could we put these into ONE sentence using a little word that means TIME?'

Teacher moves
  • Accept 'and', 'then', 'when' — affirm each
  • Bridge: 'When' makes one sentence TUCK INSIDE the other

Direct instruction

15 min

Today we meet a new kind of sentence — a COMPLEX SENTENCE. Look at MG-4. A SIMPLE sentence has ONE independent clause: 'The dog ran.' A COMPOUND sentence joins two independent clauses with FANBOYS + comma: 'The dog ran, and the cat watched.' A COMPLEX sentence has ONE independent clause plus ONE SUBORDINATE CLAUSE — a clause that depends on the other to be a full sentence. 'When the dog ran, the cat watched.' 'WHEN THE DOG RAN' can't stand alone — it's subordinate. It depends. The word WHEN is the SUBORDINATING CONJUNCTION — it joins the subordinate clause to the independent one. Today we learn TWO conjunctions: WHEN (time) and BECAUSE (cause). And we learn the COMMA RULE. Front of sentence (fronted subordinate clause): COMMA after. Back of sentence: NO COMMA. 'When the bell rang, we hurried inside.' (fronted — comma) vs. 'We hurried inside when the bell rang.' (back — no comma). 'Because the soup was cold, Mom complained.' (fronted — comma) vs. 'Mom complained because the soup was cold.' (back — no comma).

Key examples
  • Notice the subordinate clause is the one with BECAUSE in front of it. That's the test.
    model 'I climbed the rock BECAUSE I wanted to be brave.' One independent clause + one subordinate clause = complex. No comma (back position).
    prompt Combine: 'I was scared. I climbed the rock anyway.' Use BECAUSE? No — opposite meaning. Use ALTHOUGH? Yes, but we haven't met it yet. What about flipping: 'I climbed the rock because I wanted to be brave.'
  • Either order works. The comma follows the rule, not the writer's mood.
    model 'WHEN the rain stopped, we went outside.' (fronted — comma) OR 'We went outside when the rain stopped.' (back — no comma).
    prompt Combine: 'The rain stopped. We went outside.' Use WHEN.
Checks for understanding
  • Which clause is the SUBORDINATE one in 'When the bell rang, we hurried inside'?
  • Where does the comma go — fronted or back?
Media
M-3-F-GR-03-A Chart Physical / non-image

Reproduction of MG-3 at 11x17: 3x3 grid of nine subordinating-conjunction cards, color-coded by meaning category (TIME=blue: WHEN, AFTER, BEFORE, WHILE, UNTIL; CAUSE=yellow: BECAUSE, SINCE; CONTRAST=red: ALTHOUGH; CONDITION=green: IF), each with a Grade-3 example sentence. Bottom rule line: 'Front + comma; back = no comma.' For lesson 3, the WHEN and BECAUSE cards are highlighted. Print-ready, dyslexic-friendly font.

MG-3 Chart Physical / non-image

Subordinating-conjunctions anchor chart: nine cards in a 3x3 grid color-coded by meaning category. TIME (blue): WHEN, AFTER, BEFORE, WHILE, UNTIL. CAUSE (yellow): BECAUSE, SINCE. CONTRAST (red): ALTHOUGH. CONDITION (green): IF. Each card has a sentence example ('WHEN the bell rang, we hurried inside.', 'BECAUSE the soup was cold, Mom complained.', 'ALTHOUGH I was scared, I climbed the rock.', 'IF you ask kindly, the librarian will help.'). Bottom rule: 'A SUBORDINATING CONJUNCTION joins a SUBORDINATE CLAUSE to an INDEPENDENT CLAUSE. Front + comma; back = no comma.' Print-ready 11x17.

Guided practice

15 min
Tasks
  • Combine 6 kernel-sentence pairs using WHEN or BECAUSE. Apply the comma rule. Use the sentence-strip kit.
    scaffold Strips for kernel sentences + conjunction cards + red comma sticker dots; MG-3 anchor at table
  • Sort 8 already-combined sentences as fronted (needs comma) or back (no comma).
    scaffold 2-column sort mat
Media
M-3-F-GR-03-B Manipulative Physical / non-image

Photo of the recommended classroom kit: 12 sentence-strip kernels (color-coded subject in orange, verb in green, rest in black), 9 subordinating-conjunction strips (color by meaning category), and a sheet of red comma sticker dots. Children physically arrange strips on a desk to build complex sentences and PLACE the red comma sticker where the rule says it goes. Print-ready 4x6 catalog photo for materials reference.

Formative assessment

3 min
Exit ticket
  • Write one complex sentence with WHEN (fronted, with comma).
  • Write one complex sentence with BECAUSE (back, no comma).
scoring Both correctly formed with right comma = mastery; one correct = practicing; neither = reteach with strips in lesson 5.

Closure

2 min
Moves
  • Hold up your sentence-strip combination.
  • Predict: tomorrow we meet Tier-2 Set 7 — narrator verbs like WHISPERED and EXCLAIMED.

Homework

10 min
Tasks
  • Write 2 complex sentences about your day — one with WHEN (fronted), one with BECAUSE (back). Underline the subordinate clause.

Exercises in this lesson

eng.g3.f.ex_05
Combine each pair into one complex sentence using WHEN or BECAUSE. Apply the fronted-comma rule. (1) The bell rang. We hurried inside....
 combine with when because · diff 2
eng.g3.f.ex_06
Sort these 8 complex sentences into FRONTED (subordinate clause first, comma needed) or BACK (subordinate clause last, no comma needed)....
 fronted back sort · diff 2

Differentiation

Scaffolds
  • Pre-printed kernel pairs (fewer options)
  • Sentence-strip kit with color-coded comma cue
  • Pre-marked fronted vs. back templates
Extensions
  • Combine a kernel pair THREE ways: simple (just AND), compound (with comma + FANBOYS), complex (with WHEN or BECAUSE).
  • Find one WHEN or BECAUSE sentence in your current orientation draft.
English Learners
  • Bilingual MG-3 with Spanish cognates (cuando = when, porque = because)
  • Slower oral combine demonstration
Ieps 504s
  • Strip-only manipulative (no writing required)
  • Reduced target: 3 combinations instead of 6
  • Pre-placed comma sticker dots

Teacher notes

The fronted-vs-back comma rule is the single most useful punctuation rule of the term and will be revisited at least four more times (lessons 5, 8, 11, 14). The physical sentence-strip kit is non-negotiable for the first three lessons — children who only see the rule on a chart often fail to internalize it. Plan for at least one child to write a fragment ('Because the soup was cold.') and use it as a teaching moment — a subordinate clause alone is not a sentence. Mark it gently but explicitly.