Personal pronouns: When to hook at the end of verb and when to keep separate?

Question

I am learning Spanish with the Michel Thomas Method. I am a bit confused with when to put 'lo' at the start of a phrase and when to hook it on to the verb.

Answer 1

I can think of two potential scenarios where you might want to add the direct object pronoun to the end of the phrase

1) Commands - a direct object pronoun (DOP) is always attached at the end of an affirmative command. For negative commands the DOP must come in front of the verb, but after the negative word (no, nunca, etc.)

Léalo - Read it

Sácala - Take it out

No lo leas - Don’t read it

Nunca la saques - Don’t take it out

2) Infinitive and Present Participles - when a sentence includes a verb in the infinitive, often times after an already conjugated verb, you can choose to put the DOP in front of the conjugated verb, or attach it to the end of the infinitive.

Lo voy a comprar. - I am going to buy it.

Voy a comprarlo. - I am going to buy it.

When a sentence includes a present participle, also known as a gerund verb, (Verbs ending in -ing in English) you can choose to attach the DOP to the end of the gerund or place it in front of the conjugated estar form.

Yo la estoy limpiando. - I am cleaning it.

Yo estoy limpiándola. - I am cleaning it.