SN4 ""

No	Pattern	Freq
1	it be often [adj] [verb]	213
2	it be often [adj] [to-vb]	211
3	it is often [adj] [verb]	189
4	it be often difficult [verb]	72
5	it be often possible [verb]	41
6	it be often necessary [verb]	22
7	it be often hard [verb]	14
8	it was often [adj] [verb]	12
9	it 's often [adj] [verb]	12
10	it be often [adj] tell	10
11	it be often [adj] to tell	10
12	it be often useful [verb]	9
13	it be often impossible [verb]	9
14	it be often [adj] to find	7
15	it be often [adj] to use	7
16	it be often [adj] use	7
17	it be often [adj] find	7
18	it be often helpful [verb]	6
19	it be often [adj] see	6
20	it be often [adj] to see	6
21	it be often [adj] think	5
22	it be often [adj] to make	5
23	it be often [adj] to determine	5
24	it be often [adj] get	5
25	it be often [adj] know	5
26	it be often [adj] make	5
27	it be often [adj] determine	5
28	it be often [adj] to think	5
29	it be often [adj] to know	5
30	it be often [adj] to get	5