SN4 ""

No	Pattern	Freq
1	[conj] it is difficult know	17
2	[noun] it is difficult know	8
3	[coord] it is difficult know	7
4	[subord] it is difficult know	6
5	and it is difficult know	5
6	[noun sg] it is difficult know	5
7	and it is difficult know	5
8	it is [adv] difficult know	14
9	it is [adv] difficult know	14
10	it is difficult know [adv]	22
11	it is difficult know [Wh adv]	20
12	it is difficult know [pron]	17
13	it is difficult know [Wh det]	16
14	it is difficult know how	15
15	it is difficult know how	15
16	it is difficult know [conj]	14
17	it is difficult know [subord]	14
18	it is difficult know whether	13
19	it is difficult know whether	13
20	it is difficult know what	11
21	it is difficult know what	11
22	it is difficult know which	5
23	it is difficult know which	5
24	it is difficult know where	5
25	it is difficult know where	5