SN4 ""

No	Pattern	Freq
1	[noun] to the problem of	294
2	[noun sg] to the problem of	245
3	solution to the problem of	125
4	solution to the problem of	98
5	[verb] to the problem of	71
6	[noun pl] to the problem of	48
7	approach to the problem of	35
8	answer to the problem of	33
9	approach to the problem of	31
10	answer to the problem of	29
11	solutions to the problem of	27
12	[vb pp] to the problem of	24
13	[adj] to the problem of	21
14	[adj] to the problem of	20
15	[adv] to the problem of	20
16	response to the problem of	20
17	response to the problem of	17
18	attention to the problem of	14
19	[adv] to the problem of	14
20	attention to the problem of	14
21	[to-vb] to the problem of	11
22	[vb infin] to the problem of	10
23	[vb base] to the problem of	9
24	[vb -s] to the problem of	8
25	return to the problem of	8
26	relate to the problem of	8
27	add to the problem of	7
28	[v-ing] to the problem of	7
29	[adv prt] to the problem of	6
30	[conj] to the problem of	6