SN4 ""

No	Pattern	Freq
1	have become a [adj] [noun]	642
2	have become a [adj] [noun sg]	634
3	have become a [adj] [noun]	472
4	has become a [adj] [noun]	334
5	had become a [adj] [noun]	211
6	have become an [adj] [noun]	172
7	have become a [adj] [noun]	56
8	have become a [adj] part	45
9	have become a [adj] part	45
10	have become a major [noun]	40
11	have become a important [noun]	26
12	have become a [adj] feature	21
13	have become a [adj] feature	21
14	have become a [adj] issue	20
15	have become a [adj] issue	20
16	to have become a [adj] [noun]	18
17	have become a regular [noun]	15
18	have become a [adj] [noun]	15
19	have become a [adj] problem	13
20	have become a [adj] problem	13
21	have become a political [noun]	12
22	have become a integral [noun]	10
23	have become a popular [noun]	10
24	have become a [adj] force	10
25	have become a [adj] force	10
26	have become a national [noun]	10
27	have become a central [noun]	9
28	have become a [adj] factor	9
29	have become a [adj] factor	9
30	have become a real [noun]	8