SN4 ""

No	Pattern	Freq
1	it become [adj]	1495
2	it become [adj]	1385
3	it became [adj]	900
4	it becomes [adj]	537
5	it become clear	395
6	it become clear	385
7	it become apparent	165
8	it become apparent	165
9	it become possible	90
10	it become possible	90
11	it become obvious	85
12	it become obvious	85
13	it become necessary	63
14	it become necessary	63
15	it become evident	60
16	it become evident	60
17	it become [adj -er]	54
18	it become difficult	33
19	it become difficult	33
20	it become [det]	30
21	it become available	26
22	it become available	26
23	it become impossible	23
24	it become [num]	23
25	it become impossible	23
26	it become [adj]	22
27	it become important	17
28	it become important	17
29	it become more	16
30	it become more	16