SN4 ""

No	Pattern	Freq
1	[verb] [been] [verb] for centuries	37
2	[verb] been [verb] for century	37
3	have [been] [verb] for century	37
4	[verb] [been] [vb pp] for century	32
5	[vb -s] [been] [verb] for century	20
6	has [been] [verb] for century	18
7	[vb base] [been] [verb] for century	10
8	have [been] [verb] for century	10
9	[vb past] [been] [verb] for century	7
10	had [been] [verb] for century	7
11	[verb] [been] [v-ing] for century	5