SN4 ""

No	Pattern	Freq
1	have been [v-ing] for [num] [noun]	159
2	have been [v-ing] for [num] [noun pl]	156
3	have been [v-ing] for [num] year	104
4	have been [v-ing] for [num] years	103
5	has been [v-ing] for [num] [noun]	56
6	had been [v-ing] for [num] [noun]	47
7	have been [v-ing] for three [noun]	21
8	have been [v-ing] for two [noun]	19
9	have been [v-ing] for [num] [noun]	19
10	have been running for [num] [noun]	19
11	have been [v-ing] for [num] hour	18
12	have been [v-ing] for [num] hours	17
13	's been [v-ing] for [num] [noun]	14
14	have been going for [num] [noun]	14
15	've been [v-ing] for [num] [noun]	13
16	have been missing for [num] [noun]	13
17	have been [v-ing] for [num] months	12
18	have been [v-ing] for [num] month	12
19	have been [v-ing] for [num] day	12
20	have been [v-ing] for [num] days	12
21	have been [v-ing] for five [noun]	11
22	have been working for [num] [noun]	9
23	have been [v-ing] for twenty [noun]	9
24	have been [v-ing] for ten [noun]	8
25	have been [v-ing] for six [noun]	8
26	'd been [v-ing] for [num] [noun]	7
27	have been travelling for [num] [noun]	7
28	have been flying for [num] [noun]	7
29	have been trying for [num] [noun]	6
30	have been [v-ing] for [num] week	6