SN4 ""

No	Pattern	Freq
1	it is [adv] [vb pp] [conj]	1354
2	it is [adv] [vb pp] that	1169
3	it is [adv] [vb pp] [that]	1169
4	it is [adv] [vb pp] that	1169
5	it is well [vb pp] [conj]	177
6	it is generally [vb pp] [conj]	168
7	it is often [vb pp] [conj]	163
8	it is [adv] known [conj]	149
9	it is [adv] [vb pp] [coord]	119
10	it is also [vb pp] [conj]	115
11	it is [adv] assumed [conj]	109
12	it is now [vb pp] [conj]	108
13	it is [adv] [vb pp] and	100
14	it is [adv] [vb pp] and	100
15	it is [adv] said [conj]	98
16	it is sometimes [vb pp] [conj]	97
17	it is [adv] accepted [conj]	93
18	it is widely [vb pp] [conj]	92
19	it is [adv] argued [conj]	73
20	it is [adv] [vb pp] [subord]	66
21	it is [adv] believed [conj]	56
22	it is [adv] suggested [conj]	53
23	it is [adv] recognised [conj]	49
24	it is [adv] agreed [conj]	42
25	it is [adv] established [conj]	39
26	it is [adv] [vb pp] as	37
27	it is [adv] [vb pp] as	37
28	it is [adv] thought [conj]	36
29	it is commonly [vb pp] [conj]	31
30	it is [adv] recommended [conj]	30