SN4 ""

No	Pattern	Freq
1	[noun] for a [adj] period	301
2	[noun sg] for a [adj] period	225
3	[verb] for a [adj] period	176
4	[vb pp] for a [adj] period	97
5	[adv] for a [adj] period	72
6	[adv] for a [adj] period	54
7	[noun pl] for a [adj] period	51
8	[adj] for a [adj] period	49
9	[adj] for a [adj] period	38
10	[conj] for a [adj] period	33
11	[pron] for a [adj] period	33
12	[pers pn] for a [adj] period	28
13	[vb infin] for a [adj] period	24
14	[to-vb] for a [adj] period	19
15	[noun prp] for a [adj] period	19
16	[coord] for a [adj] period	18
17	only for a [adj] period	17
18	only for a [adj] period	17
19	[adv prt] for a [adj] period	16
20	[be] for a [adj] period	14
21	them for a [adj] period	14
22	[v-ing] for a [adj] period	14
23	be for a [adj] period	14
24	they for a [adj] period	14
25	last for a [adj] period	12
26	and for a [adj] period	12
27	[subord] for a [adj] period	12
28	and for a [adj] period	12
29	[vb past] for a [adj] period	11
30	continue for a [adj] period	8