---
title: Identify the means by which a bat determines the position of obstacl… — What sound is: wobbles in the air · tree and pragmatics
description: Identify the means by which a bat determines the position of obstacles in darkness. Exam question 4 of lesson 17 «What sound is: wobbles in the air» of the physics 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 4 · What sound is: wobbles in the air

<!-- .ven lang=en -->
Identify the means by which a bat determines the position of obstacles in darkness.

<!-- .vintro -->
**Mova's choice:** option 1 · **The right answer:** option 2 · wrong ✗ · **Who acts:** you, the, bat · **What happens:** identify, mean, determine · **To what, where:** position

<!-- .vabout -->
This is exam question 4 of lesson 17 «What sound is: wobbles in the air» of the physics 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/physics/17-what-sound-is-wobbles-in-the-air/#e4).

## The question {#question}

```conllu
# sent_id = question:physics:17-what-sound-is-wobbles-in-the-air:e4:1
# text = Identify the means by which a bat determines the position of obstacles in darkness.
1	Identify	identify	VERB	VB	Mood=Imp|VerbForm=Fin	0	root	_	_
2	the	the	DET	DT	Definite=Def|PronType=Art	3	nsubj	_	_
3	means	mean	VERB	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	1	ccomp	_	_
4	by	by	ADP	IN	_	5	case	_	_
5	which	which	PRON	WDT	PronType=Rel	8	obl	_	_
6	a	a	DET	DT	Definite=Ind|PronType=Art	7	det	_	_
7	bat	bat	NOUN	NN	Number=Sing	8	nsubj	_	_
8	determines	determine	VERB	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	3	parataxis	_	_
9	the	the	DET	DT	Definite=Def|PronType=Art	10	det	_	_
10	position	position	NOUN	NN	Number=Sing	8	obj	_	_
11	of	of	ADP	IN	_	12	case	_	_
12	obstacles	obstacle	NOUN	NNS	Number=Plur	10	nmod	_	_
13	in	in	ADP	IN	_	14	case	_	_
14	darkness	darkness	NOUN	NN	Number=Sing	12	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* |  |  |  |  |  | vn characterize-29.2-1-1 «NP V S\_ING»: agent=Agent clause=Theme |
| 2 | **mean** | present | the |  |  |  |  |  | vn intend-61.2-1 «NP V S»: agent=Agent |
| 3 | **determine** | present | a bat | the position of obstacles in darkness |  |  |  |  | vn discover-84 «NP V NP»: agent=Agent position=Topic |

<!-- .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 -->
By vision unaffected by the absence of light

```conllu
# sent_id = question:physics:17-what-sound-is-wobbles-in-the-air:e4:o1:1
# text = By vision unaffected by the absence of light
1	By	by	ADP	IN	_	2	case	_	_
2	vision	vision	NOUN	NN	Number=Sing	0	root	_	_
3	unaffected	unaffected	ADJ	JJ	Degree=Pos	2	amod	_	_
4	by	by	ADP	IN	_	6	case	_	_
5	the	the	DET	DT	Definite=Def|PronType=Art	6	det	_	_
6	absence	absence	NOUN	NN	Number=Sing	3	obl	_	_
7	of	of	ADP	IN	_	8	case	_	_
8	light	light	NOUN	NN	Number=Sing	6	nmod	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **absent** |  |  | light |  |  |  |  | nom absence «state transitive»: of=patient |

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

<!-- .ven lang=en -->
By the reception of echoes of its own high-pitched calls

```conllu
# sent_id = question:physics:17-what-sound-is-wobbles-in-the-air:e4:o2:1
# text = By the reception of echoes of its own high-pitched calls
1	By	by	ADP	IN	_	3	case	_	_
2	the	the	DET	DT	Definite=Def|PronType=Art	3	det	_	_
3	reception	reception	NOUN	NN	Number=Sing	0	root	_	_
4	of	of	ADP	IN	_	5	case	_	_
5	echoes	echo	NOUN	NNS	Number=Plur	3	nmod	_	_
6	of	of	ADP	IN	_	12	case	_	_
7	its	its	PRON	PRP$	Case=Gen|Gender=Neut|Number=Sing|Person=3|Poss=Yes|PronType=Prs	12	nmod:poss	_	_
8	own	own	ADJ	JJ	Degree=Pos	12	amod	_	_
9	high	high	ADJ	JJ	Degree=Pos	11	compound	_	SpaceAfter=No
10	-	-	PUNCT	HYPH	_	9	punct	_	SpaceAfter=No
11	pitched	pitch	VERB	VBN	Tense=Past|VerbForm=Part|Voice=Pass	12	amod	_	_
12	calls	call	NOUN	NNS	Number=Plur	5	nmod	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **pitch** | participle |  |  |  |  |  |  | vn throw-17.1-1 «NP V NP»: agent=Agent |
| 2 | **receive** |  |  | echoes of reception's own pitched calls |  |  |  |  | nom reception «communication transitive»: of=patient |
| 3 | **call** |  | reception |  |  |  |  |  | nom call «communication transitive»: poss=agent |

### Option 3 {#o3}

<!-- .ven lang=en -->
By the sense of smell alone

```conllu
# sent_id = question:physics:17-what-sound-is-wobbles-in-the-air:e4:o3:1
# text = By the sense of smell alone
1	By	by	ADP	IN	_	3	case	_	_
2	the	the	DET	DT	Definite=Def|PronType=Art	3	det	_	_
3	sense	sense	NOUN	NN	Number=Sing	0	root	_	_
4	of	of	ADP	IN	_	5	case	_	_
5	smell	smell	NOUN	NN	Number=Sing	3	nmod	_	_
6	alone	alone	ADV	RB	_	5	advmod	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **sense** |  |  | smell |  |  |  |  | nom sense «cognition transitive»: of=patient |

### Option 4 {#o4}

<!-- .ven lang=en -->
By memory of all previous flights

```conllu
# sent_id = question:physics:17-what-sound-is-wobbles-in-the-air:e4:o4:1
# text = By memory of all previous flights
1	By	by	ADP	IN	_	2	case	_	_
2	memory	memory	NOUN	NN	Number=Sing	0	root	_	_
3	of	of	ADP	IN	_	6	case	_	_
4	all	all	DET	DT	PronType=Tot	6	det	_	_
5	previous	previous	ADJ	JJ	Degree=Pos	6	amod	_	_
6	flights	flight	NOUN	NNS	Number=Plur	2	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.

<!-- /div -->

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- ← previous: [What sound is: wobbles in the air, exam 3](https://md.mova.elamur.ai/free/en/corpora/questions/physics/17-what-sound-is-wobbles-in-the-air/e3/)
- next →: [Thunder, sirens and how fast sound tra…, test 1](https://md.mova.elamur.ai/free/en/corpora/questions/physics/18-thunder-sirens-and-how-fast-sound-travels/t1/)
- ↑ back to [What sound is: wobbles in the air](https://md.mova.elamur.ai/free/en/corpora/questions/physics/17-what-sound-is-wobbles-in-the-air/)