---
title: Identify the principal cause of the darkening of silver tableware in… — Tarnish and how metals change · tree and pragmatics
description: Identify the principal cause of the darkening of silver tableware in ordinary domestic conditions. Exam question 1 of lesson 14 «Tarnish and how metals change» of the chemistry course of Mova's primary school, with the dependency tree and pragmatics of the question and of each option; Mova's choice 
---

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# Exam question 1 · Tarnish and how metals change

<!-- .ven lang=en -->
Identify the principal cause of the darkening of silver tableware in ordinary domestic conditions.

<!-- .vintro -->
**Mova's choice:** option 1 · **The right answer:** option 2 · wrong ✗ · **Who acts:** you · **What happens:** identify, cause, darken · **To what, where:** principal cause, darkening, silver tableware

<!-- .vabout -->
This is exam question 1 of lesson 14 «Tarnish and how metals change» of the chemistry course of Mova's primary school, asked in stiff, formal language. The page gives the question's syntax tree — a dependency tree in the style of Universal Dependencies — and its pragmatics clause by clause, then the 4 options as the student saw them, each with its tree and pragmatics. Every text is parsed by Mova itself. How the student answered it, with the score of every option and why: [the test at school](https://md.mova.elamur.ai/free/en/school-run/chemistry/14-tarnish-and-how-metals-change/#e1).

## The question {#question}

```conllu
# sent_id = question:chemistry:14-tarnish-and-how-metals-change:e1:1
# text = Identify the principal cause of the darkening of silver tableware in ordinary domestic conditions.
1	Identify	identify	VERB	VB	Mood=Imp|VerbForm=Fin	0	root	_	_
2	the	the	DET	DT	Definite=Def|PronType=Art	4	det	_	_
3	principal	principal	ADJ	JJ	Degree=Pos	4	amod	_	_
4	cause	cause	NOUN	NN	Number=Sing	1	obj	_	_
5	of	of	ADP	IN	_	7	case	_	_
6	the	the	DET	DT	Definite=Def|PronType=Art	7	det	_	_
7	darkening	darkening	NOUN	NN	Number=Sing	4	nmod	_	_
8	of	of	ADP	IN	_	10	case	_	_
9	silver	silver	NOUN	NN	Number=Sing	10	compound	_	_
10	tableware	tableware	NOUN	NN	Number=Sing	7	nmod	_	_
11	in	in	ADP	IN	_	14	case	_	_
12	ordinary	ordinary	ADJ	JJ	Degree=Pos	14	amod	_	_
13	domestic	domestic	ADJ	JJ	Degree=Pos	14	amod	_	_
14	conditions	condition	NOUN	NNS	Number=Plur	10	nmod	_	SpaceAfter=No
15	.	.	PUNCT	.	_	1	punct	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **identify** | imperative | you *not said here* | the principal cause of the darkening of silver tableware in ordinary domestic conditions |  |  |  |  | vn characterize-29.2-1-1 «NP V NP S\_ING»: agent=Agent cause=Theme |
| 2 | **cause** |  |  | the darkening of silver tableware in ordinary domestic conditions |  |  |  |  | nom cause «event transitive»: of=patient |
| 3 | **darken** |  |  | silver tableware in ordinary domestic conditions |  |  |  |  | nom darkening «act transitive»: of=patient |

<!-- .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.

## The options {#options}

### Option 1 · ← Mova's choice {#o1}

<!-- .ven lang=en -->
Absorption of moisture from the atmosphere

```conllu
# sent_id = question:chemistry:14-tarnish-and-how-metals-change:e1:o1:1
# text = Absorption of moisture from the atmosphere
1	Absorption	absorption	NOUN	NN	Number=Sing	0	root	_	_
2	of	of	ADP	IN	_	3	case	_	_
3	moisture	moisture	NOUN	NN	Number=Sing	1	nmod	_	_
4	from	from	ADP	IN	_	6	case	_	_
5	the	the	DET	DT	Definite=Def|PronType=Art	6	det	_	_
6	atmosphere	atmosphere	NOUN	NN	Number=Sing	1	nmod	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **absorb** |  |  | moisture |  | the atmosphere |  |  | nom absorption «process transitive»: of=patient from=place |

### Option 2 · ✓ the right answer {#o2}

<!-- .ven lang=en -->
Reaction with sulphur-containing gases in the air

```conllu
# sent_id = question:chemistry:14-tarnish-and-how-metals-change:e1:o2:1
# text = Reaction with sulphur-containing gases in the air
1	Reaction	reaction	NOUN	NN	Number=Sing	0	root	_	_
2	with	with	ADP	IN	_	6	case	_	_
3	sulphur	sulphur	NOUN	NN	Number=Sing	5	compound	_	SpaceAfter=No
4	-	-	PUNCT	HYPH	_	3	punct	_	SpaceAfter=No
5	containing	contain	VERB	VBG	VerbForm=Ger	6	amod	_	_
6	gases	gas	NOUN	NNS	Number=Plur	1	nmod	_	_
7	in	in	ADP	IN	_	9	case	_	_
8	the	the	DET	DT	Definite=Def|PronType=Art	9	det	_	_
9	air	air	NOUN	NN	Number=Sing	6	nmod	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **contain** | gerund |  |  |  |  |  |  | vn comprise-107.2-2 «NP V NP»: agent=Pivot |

### Option 3 {#o3}

<!-- .ven lang=en -->
Contact with oxygen alone in dry air, as in the rusting of iron

```conllu
# sent_id = question:chemistry:14-tarnish-and-how-metals-change:e1:o3:1
# text = Contact with oxygen alone in dry air, as in the rusting of iron
1	Contact	contact	NOUN	NN	Number=Sing	0	root	_	_
2	with	with	ADP	IN	_	3	case	_	_
3	oxygen	oxygen	NOUN	NN	Number=Sing	1	nmod	_	_
4	alone	alone	ADV	RB	_	1	advmod	_	_
5	in	in	ADP	IN	_	7	case	_	_
6	dry	dry	ADJ	JJ	Degree=Pos	7	amod	_	_
7	air	air	NOUN	NN	Number=Sing	1	nmod	_	SpaceAfter=No
8	,	,	PUNCT	,	_	12	punct	_	_
9	as	as	ADP	IN	_	12	case	_	_
10	in	in	ADP	IN	_	12	case	_	_
11	the	the	DET	DT	Definite=Def|PronType=Art	12	det	_	_
12	rusting	rusting	NOUN	NN	Number=Sing	1	conj	_	_
13	of	of	ADP	IN	_	14	case	_	_
14	iron	iron	NOUN	NN	Number=Sing	12	nmod	_	_
```

<!-- .note -->
The frames reader finds no event or fact in this sentence.

### Option 4 {#o4}

<!-- .ven lang=en -->
Exposure to excessive quantities of light

```conllu
# sent_id = question:chemistry:14-tarnish-and-how-metals-change:e1:o4:1
# text = Exposure to excessive quantities of light
1	Exposure	exposure	NOUN	NN	Number=Sing	0	root	_	_
2	to	to	ADP	IN	_	4	case	_	_
3	excessive	excessive	ADJ	JJ	Degree=Pos	4	amod	_	_
4	quantities	quantity	NOUN	NNS	Number=Plur	1	nmod	_	_
5	of	of	ADP	IN	_	6	case	_	_
6	light	light	NOUN	NN	Number=Sing	4	nmod	_	_
```

<!-- .note -->
The frames reader finds no event or fact in this sentence.

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**Text:** the tests of Mova's primary school, written for Mova (`world/data/school/`), as the course runner gave them to the student. **Trees:** Mova's own parse — the `en` model on the CPU, when the site is built — not checked by a teacher; they may be wrong. **Frames:** Mova's frames reader (`prag`), each text read on its own. Elamur Cosmic License.

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