| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [Wh adv] long [pers pn] have [been] [v-ing] | 15 |
|
| 2 | how long [pers pn] have [been] [v-ing] | 15 |
|
| 3 | [Wh adv] long [pers pn] have been [v-ing] | 15 |
|
| 4 | [Wh adv] long [pers pn] 've [been] [v-ing] | 6 |
|
