---
title: Identify the principal agency by which the planets are retained in t… — Gravity · tree and pragmatics
description: Identify the principal agency by which the planets are retained in their orbits. Exam question 2 of lesson 6 «Gravity» 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 · Gravity

<!-- .ven lang=en -->
Identify the principal agency by which the planets are retained in their orbits.

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

<!-- .vabout -->
This is exam question 2 of lesson 6 «Gravity» 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/6-gravity/#e2).

## The question {#question}

```conllu
# sent_id = question:world:6-gravity:e2:1
# text = Identify the principal agency by which the planets are retained in their orbits.
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	agency	agency	NOUN	NN	Number=Sing	1	obj	_	_
5	by	by	ADP	IN	_	6	case	_	_
6	which	which	PRON	WDT	PronType=Rel	10	obl	_	_
7	the	the	DET	DT	Definite=Def|PronType=Art	8	det	_	_
8	planets	planet	NOUN	NNS	Number=Plur	10	nsubj:pass	_	_
9	are	be	AUX	VBP	Mood=Ind|Number=Plur|Person=3|Tense=Pres|VerbForm=Fin	10	aux:pass	_	_
10	retained	retain	VERB	VBN	Tense=Past|VerbForm=Part|Voice=Pass	4	acl:relcl	_	_
11	in	in	ADP	IN	_	13	case	_	_
12	their	their	PRON	PRP$	Case=Gen|Number=Plur|Person=3|Poss=Yes|PronType=Prs	13	nmod:poss	_	_
13	orbits	orbit	NOUN	NNS	Number=Plur	10	obl	_	SpaceAfter=No
14	.	.	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 agency |  |  |  |  | vn characterize-29.2-1-1 «NP V NP S\_ING»: agent=Agent agency=Theme |
| 2 | **retain** | present · passive | the principal agency | the planets |  | planets's orbits |  |  | tree rules |

<!-- .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 -->
The friction of interplanetary air

```conllu
# sent_id = question:world:6-gravity:e2:o1:1
# text = The friction of interplanetary air
1	The	the	DET	DT	Definite=Def|PronType=Art	2	det	_	_
2	friction	friction	NOUN	NN	Number=Sing	0	root	_	_
3	of	of	ADP	IN	_	5	case	_	_
4	interplanetary	interplanetary	ADJ	JJ	Degree=Pos	5	amod	_	_
5	air	air	NOUN	NN	Number=Sing	2	nmod	_	_
```

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

### Option 2 {#o2}

<!-- .ven lang=en -->
The pressure of the solar wind

```conllu
# sent_id = question:world:6-gravity:e2:o2:1
# text = The pressure of the solar wind
1	The	the	DET	DT	Definite=Def|PronType=Art	2	det	_	_
2	pressure	pressure	NOUN	NN	Number=Sing	0	root	_	_
3	of	of	ADP	IN	_	6	case	_	_
4	the	the	DET	DT	Definite=Def|PronType=Art	6	det	_	_
5	solar	solar	ADJ	JJ	Degree=Pos	6	amod	_	_
6	wind	wind	NOUN	NN	Number=Sing	2	nmod	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **press** |  |  | the solar wind |  |  |  |  | nom pressure «phenomenon transitive»: of=patient |

### Option 3 · ✓ the right answer {#o3}

<!-- .ven lang=en -->
The gravitational attraction of the Sun

```conllu
# sent_id = question:world:6-gravity:e2:o3:1
# text = The gravitational attraction of the Sun
1	The	the	DET	DT	Definite=Def|PronType=Art	3	det	_	_
2	gravitational	gravitational	ADJ	JJ	Degree=Pos	3	amod	_	_
3	attraction	attraction	NOUN	NN	Number=Sing	0	root	_	_
4	of	of	ADP	IN	_	6	case	_	_
5	the	the	DET	DT	Definite=Def|PronType=Art	6	det	_	_
6	Sun	Sun	PROPN	NNP	Number=Sing	3	nmod	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **attract** |  |  | the Sun |  |  |  |  | nom attraction «phenomenon transitive»: of=patient |

### Option 4 {#o4}

<!-- .ven lang=en -->
The magnetism of the Earth

```conllu
# sent_id = question:world:6-gravity:e2:o4:1
# text = The magnetism of the Earth
1	The	the	DET	DT	Definite=Def|PronType=Art	2	det	_	_
2	magnetism	magnetism	NOUN	NN	Number=Sing	0	root	_	_
3	of	of	ADP	IN	_	5	case	_	_
4	the	the	DET	DT	Definite=Def|PronType=Art	5	det	_	_
5	Earth	Earth	PROPN	NNP	Number=Sing	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: [Gravity, exam 1](https://md.mova.elamur.ai/free/en/corpora/questions/world/6-gravity/e1/)
- next →: [Gravity, exam 3](https://md.mova.elamur.ai/free/en/corpora/questions/world/6-gravity/e3/)
- ↑ back to [Gravity](https://md.mova.elamur.ai/free/en/corpora/questions/world/6-gravity/)