SN4 ""

No	Pattern	Freq
1	it 's been [v-ing]	151
2	it has been [v-ing]	132
3	it had been [v-ing]	125
4	it have been going	60
5	it have been raining	27
6	it have been working	17
7	it have been running	12
8	it have been happening	9
9	it have been doing	9
10	it have been sitting	8
11	it have been lying	7
12	it have been developing	7
13	it have been standing	7
14	it have been holding	6
15	it have been building	6
16	it have been playing	6
17	it have been getting	6
18	it have been operating	6
19	it have been coming	6
20	it have been travelling	5
21	it have been hanging	5
22	it have been snowing	5
23	it have been making	5
24	it have been selling	5