SN4 ""

No	Pattern	Freq
1	have become a [adj] [noun sg]	632
2	have become a [adj] [noun]	471
3	has become a [adj] [noun]	334
4	had become a [adj] [noun]	210
5	have become an [adj] [noun]	171
6	have become a [adj] [noun]	56
7	have become a [adj] part	45
8	have become a [adj] part	45
9	have become a major [noun]	40
10	have become a important [noun]	26
11	have become a [adj] feature	21
12	have become a [adj] feature	21
13	have become a [adj] issue	20
14	have become a [adj] issue	20
15	to have become a [adj] [noun]	18
16	have become a regular [noun]	15
17	have become a [adj] [noun]	15
18	have become a [adj] problem	13
19	have become a [adj] problem	13
20	have become a political [noun]	12
21	have become a [adj] force	10
22	have become a popular [noun]	10
23	have become a national [noun]	10
24	have become a integral [noun]	10
25	have become a [adj] force	10
26	have become a central [noun]	9
27	have become a [adj] factor	9
28	have become a [adj] factor	9
29	have become a real [noun]	8
30	have become a familiar [noun]	8