A hands-on field guide to sentence structure
Build sentences like an architect.
Three guided levels, an infinite arena that generates fresh drills on demand, and a sentence lab. Learn the parts, then practice forever — the difficulty climbs with you.
every sentence you’ll ever write is built from parts like these — learn the parts, master the whole.
Basic · The building blocks
Subjects, verbs, and the two rules every sentence obeys. Nail these and everything above them is just decoration.
- Subject + predicate
- Fragments vs. sentences
- Capitals & end marks
- Word order
Every sentence needs two things: a subject (who or what it’s about) and a predicate (what happens). Together they express one complete thought.
The dog barked at the mail carrier.
Fragments look like sentences but are missing a part — they can’t stand alone:
Because the dog barked. Running to the door.
The 3-point checklist
- Subject + verb? Someone or something does something.
- Complete thought? It can stand alone without extra context.
- Mechanics? Capital letter to start, . ! ? to finish.
complete ✓
Intermediate · Clauses & bridges
Four sentence moods, two kinds of clauses, and the seven little conjunctions that glue whole ideas together.
- Sentence types
- Independent vs. dependent
- FANBOYS
- Compound sentences
Declarative
Tells something. “Owls hunt at night.”
Interrogative
Asks something. “Have you seen an owl?”
Imperative
Commands. “Look up.”
Exclamatory
Emotes. “That owl is huge!”
An independent clause can stand alone; a dependent clause leans on one. Because owls are silent, hunters rarely hear them.
Join two independent clauses with a comma + one of the FANBOYS to build a compound sentence:
independent clause + , + FANBOYS + independent clause = compound sentence
complete ✓
Advanced · The full machine
Complex architecture, parallel rhythm, and the discipline to never let two clauses collide in a comma splice.
- Complex & compound-complex
- Parallelism
- Run-ons & splices
- Subordination
Parallelism keeps lists in rhythm: hiking, swimming, and to ride → hiking, swimming, and riding.
Repair kit for run-ons and comma splices — pick one:
complete ✓
The Infinite Arena ♾
Drills assembled on demand from grammar blueprints — no two sessions alike, and the supply never runs out. Scaffolding is built in: three-step hints when you’re stuck, and a difficulty ladder that rises as your streak grows. Answer well to reach Tier III; a slip sends you back down to rebuild.
Pick a level, then generate your first drill. Every drill is built fresh from the blueprint engine — shorter at Tier I, longer and trickier as you climb.
The Sentence Lab
Free play. Mix a subject, a verb and an object to assemble a grammatically complete simple sentence — then test one of your own.
Subject
Verb
Object
🔀 Scrambled Words Pool (Identify word types & select 3 in order: Subject → Verb → Object)
Pick one chip from each column…
✓ Subject + verb + object = a complete simple sentence. You just built one.
Write any sentence of your own and run it through the basic mechanics checklist.
Exam Practice ★
Cambridge English style exam exercises: Multiple Choice Cloze, Open Cloze, Word Formation, and Key Word Transformation. Pick a level and exercise type to generate a brand new practice module.