Part-of-speech tags: English BNC CLAWS5

1AJ0Adjective (general or positive) (e.g. good, old, beautiful)
2AJCComparative adjective (e.g. better, older)
3AJSSuperlative adjective (e.g. best, oldest)
4AT0Article (e.g. the, a, an, no)
5AV0General adverb: an adverb not subclassified as AVP or AVQ (see below) (e.g. often, well, longer (adv.)
6AVPAdverb particle (e.g. up, off, out)
7AVQWh-adverb (e.g. when, where, how, why, wherever)
8CJCCoordinating conjunction (e.g. and, or, but)
9CJSSubordinating conjunction (e.g. although, when)
10CJTThe subordinating conjunction that
11CRDCardinal number (e.g. one, 3, fifty-five, 3609)
12DPSPossessive determiner (e.g. your, their, his)
13DT0General determiner: i.e. a determiner which is not a DTQ.
14DTQWh-determiner (e.g. which, what, whose, whichever)
15EX0Existential there
16ITJInterjection or other isolate (e.g. oh, yes, mhm, wow)
17NN0Common noun, neutral for number (e.g. aircraft, data, committee)
18NN1Singular common noun (e.g. pencil, goose, time, revelation)
19NP0Proper noun (e.g. London, Michael, Mars, IBM)
20ORDOrdinal numeral (e.g. first, sixth, 77th, last)
21PNIIndefinite pronoun (e.g. none, everything, one [as pronoun], nobody)
22PNPPersonal pronoun (e.g. I, you, them, ours)
23PNQWh-pronoun (e.g. who, whoever, whom)
24PNXReflexive pronoun (e.g. myself, yourself, itself, ourselves)
25POSThe possessive or genitive marker 's or ' (e.g. for 'Peter's or somebody else's')
26PRFThe preposition of.
27PRPPreposition (except for of)
28TO0Infinitive marker to
29UNCUnclassified items
30VBBThe present tense forms of the verb BE, except for is, 's: i.e. am, are, 'm, 're and be
31VBDThe past tense forms of the verb BE: was and were
32VBGThe -ing form of the verb BE: being
33VBIThe infinitive form of the verb BE: be
34VBNThe past participle form of the verb BE: been
35VBZThe -s form of the verb BE: is, 's
36VDBThe finite base form of the verb BE: do
37VDDThe past tense form of the verb DO: did
38VDGThe -ing form of the verb DO: doing
39VDIThe infinitive form of the verb DO: do
40VDNThe past participle form of the verb DO: done
41VDZThe -s form of the verb DO: does, 's
42VHBThe finite base form of the verb HAVE: have, 've
43VHDThe past tense form of the verb HAVE: had, 'd
44VHGThe -ing form of the verb HAVE: having
45VHIThe infinitive form of the verb HAVE: have
46VHNThe past participle form of the verb HAVE: had
47VHZThe -s form of the verb HAVE: has, 's
48VM0Modal auxiliary verb (e.g. will, would, can, could, 'll, 'd)
49VVBThe finite base form of lexical verbs (e.g. forget, send, live, return)
50VVDThe past tense form of lexical verbs (e.g. forgot, sent, lived, returned)
51VVGThe -ing form of lexical verbs (e.g. forgetting, sending, living, returning)
52VVIThe infinitive form of lexical verbs (e.g. forget, send, live, return)
53VVNThe past participle form of lexical verbs (e.g. forgotten, sent, lived, returned)
54VVZThe -s form of lexical verbs (e.g. forgets, sends, lives, returns)
55XX0The negative particle not or n't
56ZZ0Alphabetical symbols (e.g. A, a, B, b, c, d)

More info: http://www.natcorp.ox.ac.uk/docs/c5spec.html