Two Verbs, Two Options
When a sentence has a conjugated verb followed immediately by an infinitive (like quiero limpiar or puedes planchar), you have two choices for where to place the object pronoun.
You can put the pronoun right before the conjugated verb:
| Can you iron it soon? | ¿La puedes planchar pronto? |
| The plant is dry, I want to water it. | La planta está seca, la quiero regar. |
Alternatively, you can attach the pronoun directly to the end of the infinitive, combining them into a single word. Both options are perfectly natural and mean exactly the same thing!
| The shirt is here, I want to iron it. | La camisa está aquí, quiero plancharla. |
| I need to sweep it with the broom. | Necesito barrerlo con la escoba. |
Pronouns with Continuous Actions
This same flexibility applies when you use the present progressive—a conjugated form of estar followed by a gerund (verbs ending in -ando or -iendo, like lavando or barriendo).
You can place the pronoun before the conjugated verb (estar):
| The floor is dirty, I am sweeping it. | El piso está sucio, lo estoy barriendo. |
| The plate is dirty, I am washing it. | El plato está sucio, lo estoy lavando. |
Or, you can attach it directly to the end of the gerund. Notice that when you attach a pronoun to a gerund, you must add a written accent mark to keep the spoken stress on the correct syllable (usually over the a in -ando or the e in -iendo).
| The mirror is in the bathroom, I am cleaning it. | El espejo está en el baño, estoy limpiándolo. |