Cleft sentence

A cleft sentence breaks a simple statement into two clauses in order to emphasise one part of it — turning 'the second key worked' into 'it was the second key that worked'.

The second key worked. Perfectly clear, and perfectly flat: every element gets the same stress. Cleave it in two and you can aim it.

• It-cleft: It was the second key that worked. — not the first one.
• What-cleft (pseudo-cleft): What worked was the second key.
• Reversed what-cleft: The second key was what worked.

Each version costs a few extra words and buys one thing: the reader now knows which element is contested. Clefting is how English marks contrast without italics, and it is the most useful answer to the note this line should land harder but I do not want to bold anything.

It works particularly well in dialogue, because it is how people actually argue: It was not the lock that failed. What I asked for was a straight answer. The construction carries an implied opposition, and readers hear it.

The caution is that clefting adds a dummy it and an extra verb, so a page of cleft sentences reads as padded and slightly fussy. Use it where the emphasis is genuinely in dispute. Where it is not, the plain sentence is faster, and speed is its own emphasis.