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Adverbs
In the English XTAG grammar, VP and S-modifying adverbs anchor the
auxiliary trees vxARB and ARBvx, ARBs,
sARB,20.5 allowing pre and post modification of S's and VP's.
Besides the VP and S-modifying adverbs, the grammar includes adverbs
that modify other categories. Examples of adverbs modifying an
adjective, an adverb, a PP, an NP, and a determiner are shown in
((359))-((366)). (See Sections 24.1.5 and
24.4.1 for discussion of the puARBpuvx and
spuARB, which handle pre-verbal parenthetical adverbs and
post-sentential comma-separated adverbs.)
- Modifying an adjective
(358)0(358
- (359)
- extremely good
(359)0(359
- (360)
- rather tall
(360)0(360
- (361)
- rich enough
- Modifying an adverb
(361)0(361
- (362)
- oddly enough
(362)0(362
- (363)
- very well
- Modifying a PP
(363)0(363
- (364)
- right through the wall
- Modifying a NP
(364)0(364
- (365)
- quite some time
- Modifying a determiner
(365)0(365
- (366)
- exactly five men
XTAG has separate trees for each of the modified categories and for pre and
post modification where needed. The kind of treatment given to adverbs here is
very much in line with the base-generation approach proposed by [#!Ernst84!#],
which assumes all positions where an adverb can occur to be base-generated, and
that the semantics of the adverb specifies a range of possible positions
occupied by each adverb. While the relevant semantic features of the adverbs
are not currently implemented, implementation of semantic features is scheduled
for future work. The trees for adverb anchored modifiers are very similar in
form to the adjective anchored modifier trees. Examples of two of the basic
adverb modifier trees are shown in Figure 20.10.
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1.0in |
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(a) |
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(b) |
- {Adverb Trees for pre-modification of S: $\beta$ARBs (a) and post-modification of a VP: $\beta$vxARB (b)
Like the adjective anchored trees, these trees also have the NA
constraint on the foot node to restrict the number of derivations
produced for a sequence of adverbs. Features of the modified category
are passed from the foot node to the root node, reflecting correctly
that these types of properties are unaffected by the adjunction of an
adverb. A summary of the categories modified and the position of
adverbs is given in Table 20.2.
|
Position with respect to item modified |
Category Modified |
Pre |
Post |
S |
ARBs |
sARB |
VP |
ARBvx,puARBpuvx |
vxARB |
A |
ARBa |
aARB |
PP |
ARBpx |
pxARB |
ADV |
ARBarb |
arbARB |
NP |
ARBnx |
|
Det |
ARBd |
|
- {Simple Adverb Anchored Modifiers
In the English XTAG grammar, no traces are posited for wh-adverbs, in-line with
the base-generation approach ([#!Ernst84!#]) for various positions of
adverbs. Since convincing arguments have been made against traces for adjuncts
of other types (e.g. [#!Baltin!#]), and since the reasons for wanting traces
do not seem to apply to adjuncts, we make the general assumption in our grammar
that adjuncts do not leave traces. Sentence initial wh-adverbs select the same
auxiliary tree used for other sentence initial adverbs (ARBs) with the
feature <wh>=+. Under this treatment, the derived tree for the
sentence How did you fall? is as in Figure (20.11), with
no trace for the adverb.
- {Derived tree for How did you fall?
- {Complex adverb phrase modifier: $\beta$ARBarbs
There is one more adverb modifier tree in the grammar which is not included in
Table 20.2. This tree, shown in Figure 20.12, has
a complex adverb phrase and is used for wh+ two-adverb phrases that occur
sentence initially, such as in sentence ((367)). Since how is the only
wh+ adverb, it is the only adverb that can anchor this tree.
(366)0(366
- (367)
- how quickly did Srini fix the problem ?
Focus adverbs such as only, even, just and at least
are also handled by the system. Since the syntax allows focus adverbs to
appear in practically any position, these adverbs select most of the trees
listed in Table 20.2. It is left up to the semantics or
pragmatics to decide the correct scope for the focus adverb for a given
instance. In terms of the ability of the focus adverbs to modify at different
levels of a noun phrase, the focus adverbs can modify either cardinal
determiners or noun-cardinal noun phrases, and cannot modify at the level of
noun. The tree for adverbial modification of noun phrases is in shown
Figure 20.13(a).
In addition to at least, the system handles the other two-word
adverbs, at most and up to, and the three-word as-as
adverb constructions, where an adjective substitutes between the two
occurrences of as. An example of a three-word as-as adverb
is as little as. Except for the ability of at least to
modify many different types of constituents as noted above, the
multi-word adverbs are restricted to modifying cardinal determiners.
Example sentences using the trees in Figure 20.13 are
shown in ((368))-((372)).
- Focus Adverb modifying an NP
(367)0(367
- (368)
- only a member of our crazy family could pull off that kind of a stunt .
(368)0(368
- (369)
- even a flying saucer sighting would seem interesting in comparison
with your story .
(369)0(369
- (370)
- The report includes a proposal for at least a partial impasse in negotiations .
- Multi-word adverbs modifying cardinal determiners
(370)0(370
- (371)
- at most ten people came to the party .
(371)0(371
- (372)
- They gave monetary gifts of as little as five dollars .
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ARBnx |
|
PaPd |
|
PARBd |
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(a) |
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(b) |
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(c) |
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- {Selected Focus and Multi-word Adverb Modifier trees: $\beta$ARBnx, $\beta$PaPd and $\beta$PARBd
The grammar also includes auxiliary trees anchored by multi-word adverbs
like a little, a bit, a mite, sort of, kind of, etc..
Multi-word adverbs like sort of and kind of can pre- modify
almost any non-clausal category. The only strict constraint on their
occurrence is that they can't modify nouns (in which case an adjectival
interpretation would obtain)20.6. The category which they
scope over can be directly determined from their position, except for when
they occur sentence finally in which case they are assumed to modify
VP's. The complete list of auxiliary trees anchored by these adverbs are as
follows: NPax, NPpx, NPnx, NPvx, vxNP,
NParb. Selected trees are shown in Figure 20.14, and
some examples are given in ((373))-((376)).
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|
NPax |
|
NPvx |
|
vxNP |
|
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(a) |
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(b) |
|
(c) |
|
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- {Selected Multi-word Adverb Modifier trees (for adverbs like sort of, kind of): $\beta$NPax, $\beta$NPvx, $\beta$vxNP.
(372)0(372
- (373)
- John is sort of [AP tired].
(373)0(373
- (374)
- John is sort of [PP to the right].
(374)0(374
- (375)
- John could have been sort of [VP eating the cake].
(375)0(375
- (376)
- John has been eating his cake sort of [ADV slowly].
There are some multi-word adverbs that are, however, not so free in their
distribution. Adverbs like a little, a bit, a mite modify
AP's in predicative constructions (sentences with the copula and small
clauses, AP complements in sentences with raising verbs, and AP's when they
are subcategorized for by certain verbs (e.g., John felt angry). They
can also post-modify VP's and PP's, though not as freely as
AP's20.7. Finally, they also function as
downtoners for almost all adverbials20.8. Some examples are provided in
((377))-((380)).
(376)0(376
- (377)
- Mickey is a little [AP tired].
(377)0(377
- (378)
- The medicine [VP has eased John's pain] a little.
(378)0(378
- (379)
- John is a little [PP to the right].
(379)0(379
- (380)
- John has been reading his book a little [ADV loudly].
Following their behavior as described above, the auxiliary trees they
anchor are DAax, DApx, vxDA, DAarb,
DNax, DNpx, vxDN, DNarb. Selected trees are
shown in Figure 20.15).
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vxDA |
|
DAax |
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DNpx |
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(a) |
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(b) |
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(c) |
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- {Selected Multi-word Adverb Modifier trees (for adverbs like a little, a bit): $\beta$vxDA, $\beta$DAax, $\beta$DNpx.
Next: Locative Adverbial Phrases
Up: Modifiers
Previous: Prepositions
XTAG Project
http://www.cis.upenn.edu/~xtag