---
title: Identify the instrument which employs two mirrors to permit vision o… — Mirrors, shadows and colours · tree and pragmatics
description: Identify the instrument which employs two mirrors to permit vision over obstacles. Exam question 2 of lesson 84 «Mirrors, shadows and colours» of the world course of Mova's primary school, with the dependency tree and pragmatics of the question and of each option; Mova's choice was wrong.
---

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# Exam question 2 · Mirrors, shadows and colours

<!-- .ven lang=en -->
Identify the instrument which employs two mirrors to permit vision over obstacles.

<!-- .vintro -->
**Mova's choice:** option 1 · **The right answer:** option 4 · wrong ✗ · **Who acts:** you, instrument · **What happens:** identify, employ, permit · **To what, where:** instrument, two mirrors, vision, obstacles

<!-- .vabout -->
This is exam question 2 of lesson 84 «Mirrors, shadows and colours» of the world 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/world/84-mirrors-shadows-colours/#e2).

## The question {#question}

```conllu
# sent_id = question:world:84-mirrors-shadows-colours:e2:1
# text = Identify the instrument which employs two mirrors to permit vision over obstacles.
1	Identify	identify	VERB	VB	Mood=Imp|VerbForm=Fin	0	root	_	_
2	the	the	DET	DT	Definite=Def|PronType=Art	3	det	_	_
3	instrument	instrument	NOUN	NN	Number=Sing	1	obj	_	_
4	which	which	PRON	WDT	PronType=Rel	5	nsubj	_	_
5	employs	employ	VERB	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	3	acl:relcl	_	_
6	two	two	NUM	CD	NumForm=Word|NumType=Card	7	nummod	_	_
7	mirrors	mirror	NOUN	NNS	Number=Plur	5	obj	_	_
8	to	to	PART	TO	_	9	mark	_	_
9	permit	permit	VERB	VB	VerbForm=Inf	5	advcl	_	_
10	vision	vision	NOUN	NN	Number=Sing	9	obj	_	_
11	over	over	ADP	IN	_	12	case	_	_
12	obstacles	obstacle	NOUN	NNS	Number=Plur	9	obl	_	SpaceAfter=No
13	.	.	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 instrument |  |  |  |  | vn characterize-29.2-1-1 «NP V NP S\_ING»: agent=Agent instrument=Theme |
| 2 | **employ** | present | the instrument | two mirrors |  |  |  |  | vn hire-13.5.3 «NP V NP»: agent=Agent mirror=Theme |
| 3 | **permit** | to-infinitive | the instrument *not said here* | vision |  | obstacles |  |  | vn admit-64.3-1 «NP V NP PP.location»: agent=Agent vision=Theme over obstacle=Location |

<!-- .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 -->
A filter

```conllu
# sent_id = question:world:84-mirrors-shadows-colours:e2:o1:1
# text = A filter
1	A	a	DET	DT	Definite=Ind|PronType=Art	2	det	_	_
2	filter	filter	NOUN	NN	Number=Sing	0	root	_	_
```

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

### Option 2 {#o2}

<!-- .ven lang=en -->
A prism

```conllu
# sent_id = question:world:84-mirrors-shadows-colours:e2:o2:1
# text = A prism
1	A	a	DET	DT	Definite=Ind|PronType=Art	2	det	_	_
2	prism	prism	NOUN	NN	Number=Sing	0	root	_	_
```

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

### Option 3 {#o3}

<!-- .ven lang=en -->
A sundial

```conllu
# sent_id = question:world:84-mirrors-shadows-colours:e2:o3:1
# text = A sundial
1	A	a	DET	DT	Definite=Ind|PronType=Art	2	det	_	_
2	sundial	sundial	NOUN	NN	Number=Sing	0	root	_	_
```

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

### Option 4 · ✓ the right answer {#o4}

<!-- .ven lang=en -->
A periscope

```conllu
# sent_id = question:world:84-mirrors-shadows-colours:e2:o4:1
# text = A periscope
1	A	a	DET	DT	Definite=Ind|PronType=Art	2	det	_	_
2	periscope	periscope	NOUN	NN	Number=Sing	0	root	_	_
```

<!-- .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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- ← previous: [Mirrors, shadows and colours, exam 1](https://md.mova.elamur.ai/free/en/corpora/questions/world/84-mirrors-shadows-colours/e1/)
- next →: [Mirrors, shadows and colours, exam 3](https://md.mova.elamur.ai/free/en/corpora/questions/world/84-mirrors-shadows-colours/e3/)
- ↑ back to [Mirrors, shadows and colours](https://md.mova.elamur.ai/free/en/corpora/questions/world/84-mirrors-shadows-colours/)