---
title: Platform screen doors are glass walls along the platform whose doors… — Trains and the Underground · tree and pragmatics
description: Platform screen doors are glass walls along the platform whose doors open only when the train's doors line up with them, so nobody can fall onto the track. Who acts: screen doors, doors, nobody. A sentence of the lesson «Trains and the Underground» of the technology course of Mova's primary school w
---

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# Trains and the Underground, sentence 20

<!-- .ven lang=en -->
Platform screen doors are glass walls along the platform whose doors open only when the train's doors line up with them, so nobody can fall onto the track.

<!-- .vintro -->
**Who acts:** screen doors, doors, nobody · **What happens:** be, open, line up, fall · **To what, where:** glass walls, track

<!-- .vabout -->
This is a sentence of the lesson «Trains and the Underground» of the technology 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 (screen doors, doors, nobody), what happens, when and where, as Mova's frames read it from the tree.

## The tree {#tree}

```conllu
# sent_id = school:technology:021-trains-and-the-underground.lesson:20
# text = Platform screen doors are glass walls along the platform whose doors open only when the train's doors line up with them, so nobody can fall onto the track.
# source = school lesson (ours)
# course = technology
# lesson = 021-trains-and-the-underground.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): R7-rel-agree ×1
1	Platform	platform	NOUN	NN	Number=Sing	2	compound	_	_
2	screen	screen	NOUN	NN	Number=Sing	3	compound	_	_
3	doors	door	NOUN	NNS	Number=Plur	6	nsubj	_	_
4	are	be	AUX	VBP	Mood=Ind|Number=Plur|Person=3|Tense=Pres|VerbForm=Fin	6	cop	_	_
5	glass	glass	NOUN	NN	Number=Sing	6	compound	_	Agree=R7-rel-agree|Haiku=6:amod|HaikuPos=ADJ:JJ:Degree=Pos
6	walls	wall	NOUN	NNS	Number=Plur	0	root	_	_
7	along	along	ADP	IN	_	9	case	_	_
8	the	the	DET	DT	Definite=Def|PronType=Art	9	det	_	_
9	platform	platform	NOUN	NN	Number=Sing	6	nmod	_	_
10	whose	whose	PRON	WP$	Poss=Yes|PronType=Rel	11	nmod:poss	_	_
11	doors	door	NOUN	NNS	Number=Plur	12	nsubj	_	_
12	open	open	VERB	VBP	Mood=Ind|Tense=Pres|VerbForm=Fin	6	acl:relcl	_	_
13	only	only	ADV	RB	_	19	advmod	_	_
14	when	when	ADV	WRB	PronType=Int	19	advmod	_	_
15	the	the	DET	DT	Definite=Def|PronType=Art	16	det	_	_
16	train	train	NOUN	NN	Number=Sing	18	nmod:poss	_	_
17	's	's	PART	POS	_	16	case	_	_
18	doors	door	NOUN	NNS	Number=Plur	19	nsubj	_	_
19	line	line	VERB	VBP	Mood=Ind|Tense=Pres|VerbForm=Fin	12	advcl	_	_
20	up	up	ADP	RP	_	19	compound:prt	_	_
21	with	with	ADP	IN	_	22	case	_	_
22	them	they	PRON	PRP	Case=Acc|Number=Plur|Person=3|PronType=Prs	19	obl	_	_
23	,	,	PUNCT	,	_	27	punct	_	_
24	so	so	ADV	RB	_	27	advmod	_	_
25	nobody	nobody	PRON	NN	Number=Sing|PronType=Neg	27	nsubj	_	_
26	can	can	AUX	MD	VerbForm=Fin	27	aux	_	_
27	fall	fall	VERB	VB	VerbForm=Inf	12	conj	_	_
28	onto	onto	ADP	IN	_	30	case	_	_
29	the	the	DET	DT	Definite=Def|PronType=Art	30	det	_	_
30	track	track	NOUN	NN	Number=Sing	27	obl	_	_
31	.	.	PUNCT	.	_	6	punct	_	_
```

## Pragmatics {#pragmatics}

<!-- .note -->
No stored speech act for this sentence.

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **is a** | present | screen doors | glass walls |  |  |  | along the platform | tree rules |
| 2 | **open** | present | doors |  |  |  |  |  | vn spatial\_configuration-47.6-1 «NP V»: agent=Theme |
| 3 | **line up** | present | the train's doors |  |  |  |  | with walls *= wall* | vn fill-9.8-1 «NP V NP PP.theme»: agent=Agent with they=Theme |
| 4 | **fall** | can | nobody |  |  | the track |  |  | vn escape-51.1-1 «NP V PP.initial\_location»: agent=Theme onto track=Initial\_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.

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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:technology:021-trains-and-the-underground.lesson:20`.

**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): R7-rel-agree ×1. **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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- ← previous: [Trains and the Underground, 19](https://md.mova.elamur.ai/free/en/corpora/school/technology/21-trains-and-the-underground/19/)
- next →: [Trains and the Underground, 21](https://md.mova.elamur.ai/free/en/corpora/school/technology/21-trains-and-the-underground/21/)
- ↑ back to [the lesson](https://md.mova.elamur.ai/free/en/corpora/school/technology/21-trains-and-the-underground/)