SN4 ""

No	Pattern	Freq
1	which had [verb]	4043
2	which had [vb pp]	3996
3	which had begin	122
4	which had begun	121
5	which had become	109
6	which had become	109
7	which had take	108
8	which had taken	106
9	which had led	102
10	which had lead	102
11	which had come	90
12	which had come	88
13	which had make	71
14	which had made	69
15	which had cause	62
16	which had caused	62
17	which had brought	57
18	which had bring	57
19	which had give	50
20	which had given	49
21	which had develop	46
22	which had developed	45
23	which had [to-vb]	45
24	which had go	43
25	which had gone	42
26	which had exist	40
27	which had existed	40
28	which had emerged	39
29	which had emerge	39
30	which had fallen	38