Arjun searched the heap for every piece with a subject and a working verb. He found a handful:

the bell rang
because the gate was locked
when the clock strikes ten
who stole the key

"Let's test the press," he said. "If a clause is almost a sentence, maybe some clauses are sentences already."

He set the bell rang on the belt as one line — The bell rang. — with a capital at the front and a full stop at the end.

The foreman pulled the lever. The belt carried the line in. The brass lamp flicked green, the press thumped, and out slid a notice. Three words long.

"It printed!" said the foreman. "Just three words."

"One clause standing alone is a sentence," said Arjun. "Short, but complete. The bell — subject. Rang — verb. Nothing missing."

"Then this one should print too." He set because the gate was locked on the belt, capital and full stop and all. It had a subject, the gate, and a verb, was locked.

The lamp blinked amber. The press ticked, like someone tapping a foot. Nothing came out.

"It's a clause," said the foreman. "Subject and verb. Why won't it print?"

"Say it out loud," said Grandpa. "Then stop."

"Because the gate was locked." The foreman stopped — and stood there with his mouth half open, waiting for the rest.

"You're waiting," said Arjun. "So is the press. Because the gate was locked… what happened?" He tried when the clock strikes ten and who stole the key. Amber, amber. The press waited for both.

"So some clauses lean," said Arjun slowly. "They've got a subject and a verb, but they lean on another clause and can't stand up without it. And they give themselves away with their first word." He counted the leaning words off on his fingers:

because, when, if, although, who, which, that

"The grown-up grammar books call a leaning clause a subordinate clause," said Grandpa. "Sub means under — it sits under another clause and depends on it. A clause that can stand alone, like The bell rang, is a main clause. Wren and Martin also call it a principal clause."

"A leaning clause alone is like a doorbell with no house behind it," said Grandpa. "You ring, and you wait, and nobody comes."

Arjun fetched the matching pieces and fixed the notices. This time the lamp glowed green every time.

The children waited outside because the gate was locked.
When the clock strikes ten, the fair will begin.
The police want to find the man who stole the key.

"Look at the fair notice," said Grandpa. "When the leaning clause comes first, a comma marks where it ends and the main clause begins."

The foreman frowned at the last notice. "Hang on. Who stole the key? I'd ask the Inspector that, straight out. It's a proper question. How can it be leaning?"

Arjun set the two side by side.

Who stole the key?
The police want to find the man who stole the key.

"Same four words," he said. "Two different jobs. On its own, with a capital letter and a question mark, Who stole the key? is a whole sentence. It stands up by itself and asks something. You don't wait for anything more."

"And on the notice?"

"On the notice it isn't asking anything. It's hanging onto the man — which man? The man who stole the key. There it leans. Say who stole the key in the middle of the notice and stop, and you're left waiting for the rest."

"So you can't tell a leaning clause just by its words," said Grandpa. "You tell it by what it is doing in the sentence."

The foreman slid the question into his pocket. "I'm keeping that one for the Inspector."

🗂️ Case notes
- A sentence starts with a capital letter, ends with an end mark, and has at least one clause that can stand alone. One clause on its own can be a whole sentence.
- A main clause (Wren and Martin: principal clause) makes good sense by itself. A leaning clause (Wren and Martin: dependent or subordinate clause) cannot stand by itself; it depends on a main clause.
- Test: say it and stop. If you are left waiting, it is a leaning clause. Leaning clauses often begin with because, when, if, although, who, which, that.
- When a leaning clause comes first, put a comma after it.
- The same words can stand alone in one place and lean in another. A clause is main or leaning because of the job it does in the sentence, not because of its words.