---
title: Pit vipers such as rattlesnakes have heat-sensing pits on their face… — Snakes and lizards · tree and pragmatics
description: Pit vipers such as rattlesnakes have heat-sensing pits on their faces that find warm-blooded prey in total darkness. Who acts: Pit vipers, sensing pits. A sentence of the lesson «Snakes and lizards» of the biology course of Mova's primary school with its dependency tree and the pragmatics of every c
---

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# Snakes and lizards, sentence 10

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Pit vipers such as rattlesnakes have heat-sensing pits on their faces that find warm-blooded prey in total darkness.

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**Who acts:** Pit vipers, sensing pits · **What happens:** have, sense, find · **To what, where:** sensing pits, faces, blooded prey, total darkness

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This is a sentence of the lesson «Snakes and lizards» of the biology course of Mova's primary school. The page gives its syntax tree — a dependency tree in the style of Universal Dependencies — and its pragmatics clause by clause: who acts (Pit vipers, sensing pits), what happens, when and where, as Mova's frames read it from the tree.

## The tree {#tree}

```conllu
# sent_id = school:biology:030-snakes-and-lizards.lesson:10
# text = Pit vipers such as rattlesnakes have heat-sensing pits on their faces that find warm-blooded prey in total darkness.
# source = school lesson (ours)
# course = biology
# lesson = 030-snakes-and-lizards.lesson
# annotation = Mova annot: Rust (en) → Haiku 5.5 (medium, Batches API) patches; gates UD 2.18; agreed by treeagree rules (Stanza, Trankit, spaCy trf): R5-strong ×2
1	Pit	pit	NOUN	NN	Number=Sing	2	compound	_	_
2	vipers	viper	NOUN	NNS	Number=Plur	6	nsubj	_	_
3	such	such	ADJ	JJ	Degree=Pos|ExtPos=ADP	5	case	_	_
4	as	as	ADP	IN	_	3	fixed	_	_
5	rattlesnakes	rattlesnake	NOUN	NNS	Number=Plur	2	nmod	_	_
6	have	have	VERB	VBP	Mood=Ind|Number=Plur|Person=3|Tense=Pres|VerbForm=Fin	0	root	_	_
7	heat	heat	NOUN	NN	Number=Sing	9	compound	_	_
8	-	-	PUNCT	HYPH	_	7	punct	_	_
9	sensing	sense	VERB	VBG	VerbForm=Ger	10	amod	_	_
10	pits	pit	NOUN	NNS	Number=Plur	6	obj	_	_
11	on	on	ADP	IN	_	13	case	_	_
12	their	their	PRON	PRP$	Case=Gen|Number=Plur|Person=3|Poss=Yes|PronType=Prs	13	nmod:poss	_	_
13	faces	face	NOUN	NNS	Number=Plur	10	nmod	_	_
14	that	that	PRON	WDT	PronType=Rel	15	nsubj	_	_
15	find	find	VERB	VBP	Mood=Ind|Number=Plur|Person=3|Tense=Pres|VerbForm=Fin	10	acl:relcl	_	Agree=R5-strong|Haiku=13:acl:relcl
16	warm	warm	ADJ	JJ	Degree=Pos	18	amod	_	_
17	-	-	PUNCT	HYPH	_	16	punct	_	_
18	blooded	blooded	ADJ	JJ	Degree=Pos	19	amod	_	_
19	prey	prey	NOUN	NN	Number=Sing	15	obj	_	_
20	in	in	ADP	IN	_	22	case	_	_
21	total	total	ADJ	JJ	Degree=Pos	22	amod	_	_
22	darkness	darkness	NOUN	NN	Number=Sing	15	obl	_	Agree=R5-strong|Haiku=19:nmod
23	.	.	PUNCT	.	_	6	punct	_	_
```

## Pragmatics {#pragmatics}

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- form: statement
- act: assert
- voice: narrator
- polarity: none
- teacher: kept the draft

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **have** | present | Pit vipers such rattlesnakes | sensing pits |  | vipers's faces |  |  | vn birth-28.2-1 «NP V NP»: agent=Agent pit=Patient |
| 2 | **sense** | gerund |  |  |  |  |  |  | vn see-30.1-1 «NP V S\_ING»: agent=Experiencer |
| 3 | **find** | present | sensing pits | blooded prey |  | total darkness |  |  | vn discover-84 «NP V NP»: agent=Agent prey=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.

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**Licence: [CC BY-SA 4.0](https://creativecommons.org/licenses/by-sa/4.0/)**, as the whole of Mova corpus 0.4, of which this treebank (the agreed school, `mova-school-agreed-en.conllu`) is part. The lessons were written for Mova's primary school. Sentence `school:biology:030-snakes-and-lizards.lesson:10`.

**The tree:** Mova annot: Rust (en) → Haiku 5.5 (medium, Batches API) patches; gates UD 2.18; agreed by treeagree rules (Stanza, Trankit, spaCy trf): R5-strong ×2. **The frames** are read from the tree by Mova's frames reader (`prag`) when this page is built, the lesson read in order, so a pronoun may be resolved from an earlier sentence.

See the [release 0.4](https://md.mova.elamur.ai/free/en/releases/0.4/).

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