| pipi li lukin li unpa. | The bug looks and has sex. |
By putting li before each verb, you can show how the subject, which is pipi in this case, does more than one thing.
| mi moku li pakala. | I eat and destroy. |
While li is still omitted before moku because the subject of the sentence is mi, we still use it before the second verb, pakala. Without the li there, the sentence would be chaotic and confusing. Compound sentences with sina follow this same pattern.