| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | system has be [vb pp] [adv] | 17 |
|
| 2 | system has been [vb pp] [adv] | 17 |
|
| 3 | system has [been] [vb pp] [adv] | 17 |
|
| 4 | system has [be] [vb pp] [adv] | 10 |
|
| 5 | system has [be] [vb pp] [adv prt] | 6 |
|
