---
title: Identify the principal reason for which the same face of the Moon is… — Thinking like an astronomer · tree and pragmatics
description: Identify the principal reason for which the same face of the Moon is perpetually presented to the Earth. Exam question 1 of lesson 10 «Thinking like an astronomer» 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 
---

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# Exam question 1 · Thinking like an astronomer

<!-- .ven lang=en -->
Identify the principal reason for which the same face of the Moon is perpetually presented to the Earth.

<!-- .vintro -->
**Mova's choice:** option 3 · **The right answer:** option 1 · wrong ✗ · **Who acts:** you · **What happens:** identify, present · **To what, where:** principal reason, same face

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This is exam question 1 of lesson 10 «Thinking like an astronomer» 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/10-reasoning-about-space/#e1).

## The question {#question}

```conllu
# sent_id = question:world:10-reasoning-about-space:e1:1
# text = Identify the principal reason for which the same face of the Moon is perpetually presented to the Earth.
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	reason	reason	NOUN	NN	Number=Sing	1	obj	_	_
5	for	for	ADP	IN	_	6	case	_	_
6	which	which	PRON	WDT	PronType=Rel	15	obl	_	_
7	the	the	DET	DT	Definite=Def|PronType=Art	9	det	_	_
8	same	same	ADJ	JJ	Degree=Pos	9	amod	_	_
9	face	face	NOUN	NN	Number=Sing	15	nsubj:pass	_	_
10	of	of	ADP	IN	_	12	case	_	_
11	the	the	DET	DT	Definite=Def|PronType=Art	12	det	_	_
12	Moon	Moon	PROPN	NNP	Number=Sing	9	nmod	_	_
13	is	be	AUX	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	15	aux:pass	_	_
14	perpetually	perpetually	ADV	RB	_	15	advmod	_	_
15	presented	present	VERB	VBN	Tense=Past|VerbForm=Part|Voice=Pass	4	acl:relcl	_	_
16	to	to	ADP	IN	_	18	case	_	_
17	the	the	DET	DT	Definite=Def|PronType=Art	18	det	_	_
18	Earth	Earth	PROPN	NNP	Number=Sing	15	obl	_	SpaceAfter=No
19	.	.	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 reason |  |  |  |  | vn characterize-29.2-1-1 «NP V NP S\_ING»: agent=Agent reason=Theme |
| 2 | **present** | present · passive |  | the same face of the Moon |  |  |  | for the principal reason; to the Earth; perpetually *property* | vn fulfilling-13.4.1 «NP V NP PP.recipient»: subject=Theme for which=Recipient |

<!-- .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 · ✓ the right answer {#o1}

<!-- .ven lang=en -->
Its rotation and its revolution about the Earth occupy equal periods

```conllu
# sent_id = question:world:10-reasoning-about-space:e1:o1:1
# text = Its rotation and its revolution about the Earth occupy equal periods
1	Its	its	PRON	PRP$	Case=Gen|Gender=Neut|Number=Sing|Person=3|Poss=Yes|PronType=Prs	2	nmod:poss	_	_
2	rotation	rotation	NOUN	NN	Number=Sing	9	nsubj	_	_
3	and	and	CCONJ	CC	_	5	cc	_	_
4	its	its	PRON	PRP$	Case=Gen|Gender=Neut|Number=Sing|Person=3|Poss=Yes|PronType=Prs	5	nmod:poss	_	_
5	revolution	revolution	NOUN	NN	Number=Sing	2	conj	_	_
6	about	about	ADP	IN	_	8	case	_	_
7	the	the	DET	DT	Definite=Def|PronType=Art	8	det	_	_
8	Earth	Earth	PROPN	NNP	Number=Sing	5	nmod	_	_
9	occupy	occupy	VERB	VBP	Mood=Ind|Number=Plur|Person=3|Tense=Pres|VerbForm=Fin	0	root	_	_
10	equal	equal	ADJ	JJ	Degree=Pos	11	amod	_	_
11	periods	period	NOUN	NNS	Number=Plur	9	obj	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **occupy** | present | Its rotation and its revolution about the Earth | equal periods |  |  |  |  | vn amuse-31.1 «NP V NP»: agent=Stimulus period=Experiencer |
| 2 | **rotate** |  | Its *= it* |  |  |  |  |  | nom rotation «act intransitive»: poss=agent |
| 3 | **revolt** |  | its *= it* |  |  |  |  | about the Earth | nom revolution «event intransitive»: poss=agent about=obl |

### Option 2 {#o2}

<!-- .ven lang=en -->
It does not rotate upon its axis at all

```conllu
# sent_id = question:world:10-reasoning-about-space:e1:o2:1
# text = It does not rotate upon its axis at all
1	It	it	PRON	PRP	Case=Nom|Gender=Neut|Number=Sing|Person=3|PronType=Prs	4	nsubj	_	_
2	does	do	AUX	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	4	aux	_	_
3	not	not	PART	RB	Polarity=Neg	4	advmod	_	_
4	rotate	rotate	VERB	VB	VerbForm=Inf	0	root	_	_
5	upon	upon	ADP	IN	_	7	case	_	_
6	its	its	PRON	PRP$	Case=Gen|Gender=Neut|Number=Sing|Person=3|Poss=Yes|PronType=Prs	7	nmod:poss	_	_
7	axis	axis	NOUN	NN	Number=Sing	4	obl	_	_
8	at	at	ADP	IN	_	9	case	_	_
9	all	all	DET	DT	PronType=Tot	4	obl	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **not** **rotate** | present · do-support | It |  |  | all |  | upon its axis | vn roll-51.3.1 «NP.theme V PP.source PP.trajectory PP.destination»: agent=Theme upon axis=Source at all=Trajectory |

### Option 3 · ← Mova's choice {#o3}

<!-- .ven lang=en -->
The Earth's gravity prevents it from turning

```conllu
# sent_id = question:world:10-reasoning-about-space:e1:o3:1
# text = The Earth's gravity prevents it from turning
1	The	the	DET	DT	Definite=Def|PronType=Art	2	det	_	_
2	Earth	Earth	PROPN	NNP	Number=Sing	4	nmod:poss	_	SpaceAfter=No
3	's	's	PART	POS	_	2	case	_	_
4	gravity	gravity	NOUN	NN	Number=Sing	5	nsubj	_	_
5	prevents	prevent	VERB	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	0	root	_	_
6	it	it	PRON	PRP	Case=Acc|Gender=Neut|Number=Sing|Person=3|PronType=Prs	5	obj	_	_
7	from	from	SCONJ	IN	_	8	mark	_	_
8	turning	turn	VERB	VBG	Tense=Pres|VerbForm=Part	5	advcl	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **prevent** | present | the Earth's gravity | Earth |  |  |  |  | vn forbid-64.4-1 «NP V NP»: agent=Causer it=Theme |
| 2 | **turn** | gerund | the Earth's gravity *not said here* |  |  |  |  |  | vn roll-51.3.1 «NP.theme V»: agent=Theme |

### Option 4 {#o4}

<!-- .ven lang=en -->
Its far side is permanently in darkness

```conllu
# sent_id = question:world:10-reasoning-about-space:e1:o4:1
# text = Its far side is permanently in darkness
1	Its	its	PRON	PRP$	Case=Gen|Gender=Neut|Number=Sing|Person=3|Poss=Yes|PronType=Prs	3	nmod:poss	_	_
2	far	far	ADJ	JJ	Degree=Pos	3	amod	_	_
3	side	side	NOUN	NN	Number=Sing	7	nsubj	_	_
4	is	be	AUX	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	7	cop	_	_
5	permanently	permanently	ADV	RB	_	7	advmod	_	_
6	in	in	ADP	IN	_	7	case	_	_
7	darkness	darkness	NOUN	NN	Number=Sing	0	root	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **is** | present | Its far side |  |  | darkness |  | permanently *property* | tree rules |

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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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