---
title: In a fair test you change only one thing; if two things change at on… — Olympiad: kitchen chemistry puzzles ★★★ · tree and pragmatics
description: In a fair test you change only one thing; if two things change at once, you cannot tell which one made the difference. Who acts: you, two things, one. A sentence of the lesson «Olympiad: kitchen chemistry puzzles ★★★» of the chemistry course of Mova's primary school with its dependency tree and the 
---

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# Olympiad: kitchen chemistry puzzles ★★★, sentence 17

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In a fair test you change only one thing; if two things change at once, you cannot tell which one made the difference.

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**Who acts:** you, two things, one · **What happens:** change, not tell, make · **To what, where:** one thing, fair test, difference · **Speech:** someone speaks here

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This is a sentence of the lesson «Olympiad: kitchen chemistry puzzles ★★★» of the chemistry course of Mova's primary school. The page gives its syntax tree — a dependency tree in the style of Universal Dependencies — and its pragmatics clause by clause: who acts (you, two things, one), what happens, when and where, as Mova's frames read it from the tree.

## The tree {#tree}

```conllu
# sent_id = school:chemistry:036-olympiad-kitchen-chemistry-puzzles.lesson:17
# text = In a fair test you change only one thing; if two things change at once, you cannot tell which one made the difference.
# source = school lesson (ours)
# course = chemistry
# lesson = 036-olympiad-kitchen-chemistry-puzzles.lesson
# annotation = Mova annot: Rust (en) → Haiku 5.5 (medium, Batches API) patches; gates UD 2.18; agreed by treeagree rules (Stanza, Trankit, spaCy trf): no change
1	In	in	ADP	IN	_	4	case	_	_
2	a	a	DET	DT	Definite=Ind|PronType=Art	4	det	_	_
3	fair	fair	ADJ	JJ	Degree=Pos	4	amod	_	_
4	test	test	NOUN	NN	Number=Sing	6	obl	_	_
5	you	you	PRON	PRP	Case=Nom|Person=2|PronType=Prs	6	nsubj	_	_
6	change	change	VERB	VBP	Mood=Ind|Number=Sing|Person=2|Tense=Pres|VerbForm=Fin	0	root	_	_
7	only	only	ADV	RB	_	8	advmod	_	_
8	one	one	NUM	CD	NumForm=Word|NumType=Card	9	nummod	_	_
9	thing	thing	NOUN	NN	Number=Sing	6	obj	_	_
10	;	;	PUNCT	:	_	14	punct	_	_
11	if	if	SCONJ	IN	_	14	mark	_	_
12	two	two	NUM	CD	NumForm=Word|NumType=Card	13	nummod	_	_
13	things	thing	NOUN	NNS	Number=Plur	14	nsubj	_	_
14	change	change	VERB	VBP	Mood=Ind|Number=Plur|Person=3|Tense=Pres|VerbForm=Fin	21	advcl	_	_
15	at	at	ADP	IN	_	16	case	_	_
16	once	once	ADV	RB	NumForm=Word|NumType=Mult	14	advmod	_	_
17	,	,	PUNCT	,	_	21	punct	_	_
18	you	you	PRON	PRP	Case=Nom|Person=2|PronType=Prs	21	nsubj	_	_
19	can	can	AUX	MD	VerbForm=Fin	21	aux	_	_
20	not	not	PART	RB	Polarity=Neg	21	advmod	_	_
21	tell	tell	VERB	VB	VerbForm=Inf	6	parataxis	_	_
22	which	which	DET	WDT	PronType=Int	23	det	_	_
23	one	one	NOUN	NN	Number=Sing	24	nsubj	_	_
24	made	make	VERB	VBD	Mood=Ind|Number=Sing|Person=3|Tense=Past|VerbForm=Fin	21	ccomp	_	_
25	the	the	DET	DT	Definite=Def|PronType=Art	26	det	_	_
26	difference	difference	NOUN	NN	Number=Sing	24	obj	_	_
27	.	.	PUNCT	.	_	6	punct	_	_
```

## Pragmatics {#pragmatics}

<!-- .note -->
No stored speech act for this sentence.

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| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **change** | present | you | one thing |  | a fair test |  |  | vn dress-41.1.1-1-1 «NP V NP»: agent=Agent thing=Patient |
| 2 | **change** *a condition, not said to happen* | present | two things |  |  |  |  | once *property* | vn dress-41.1.1-1-1 «NP V»: agent=Agent |
| 3 | **not** **tell** *speech: assert* | can | you |  |  |  |  |  | vn transfer\_mesg-37.1.1-1-1 «NP V how S»: agent=Agent clause=Topic |
| 4 | **make** | past | which one | the difference |  |  |  |  | vn build-26.1-1 «NP.asset V NP»: agent=Asset difference=Product |

<!-- .note -->
One row per clause the reader finds. «not said here»: a role filled from the clause above. «roles by»: a VerbNet class and frame when one fits the verb, else the reader's rules on the tree.

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**Licence: [CC BY-SA 4.0](https://creativecommons.org/licenses/by-sa/4.0/)**, as the whole of Mova corpus 0.4, of which this treebank (the agreed school, `mova-school-agreed-en.conllu`) is part. The lessons were written for Mova's primary school. Sentence `school:chemistry:036-olympiad-kitchen-chemistry-puzzles.lesson:17`.

**The tree:** Mova annot: Rust (en) → Haiku 5.5 (medium, Batches API) patches; gates UD 2.18; agreed by treeagree rules (Stanza, Trankit, spaCy trf): no change. **The frames** are read from the tree by Mova's frames reader (`prag`) when this page is built, the lesson read in order, so a pronoun may be resolved from an earlier sentence.

See the [release 0.4](https://md.mova.elamur.ai/free/en/releases/0.4/).

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