SN4 ""

No	Pattern	Freq
1	who have had [adj] [noun]	82
2	who have had [adj] [noun sg]	60
3	who have had [adj] [noun pl]	49
4	who had had [adj] [noun]	39
5	who have had [adj] [noun]	36
6	who has had [adj] [noun]	21
7	who have had [adj] experience	16
8	who have had [num] [noun]	13
9	who have had [det] [noun]	13
10	who have had [adj] experience	11
11	who 've had [adj] [noun]	8
12	who have had previous [noun]	5
13	who have had multiple [noun]	5
14	who have had [adj] surgery	5
15	who have had some [noun]	5
16	who have had previous [noun]	5
17	who have had [adj] surgery	5
18	who have had [adj] experiences	5
19	who have had multiple [noun]	5
20	who have had some [noun]	5