SN4 ""

No	Pattern	Freq
1	[vb mod] have occurred	148
2	[modal v] have occurred	148
3	[adv] have occurred	104
4	[adv] have occurred	64
5	not have occurred	40
6	[not/n't] have occurred	40
7	not have occurred	37
8	may have occurred	34
9	may have occurred	34
10	would have occurred	33
11	would have occurred	33
12	must have occurred	25
13	must have occurred	25
14	might have occurred	19
15	never have occurred	19
16	might have occurred	19
17	never have occurred	19
18	could have occurred	18
19	could have occurred	18
20	still have occurred	11
21	still have occurred	11
22	will have occurred	10
23	will have occurred	10
24	well have occurred	8
25	well have occurred	8
26	should have occurred	7
27	should have occurred	7
28	otherwise have occurred	5
29	otherwise have occurred	5
30	have occurred [prep]	104