Answer:
1. Tienes que mandarles el cheque a los muchachos. Es urgente que se lo mandes hoy.
2. No olvides pedirle el aumento al jefe. Es necesario pedírselo pronto.
3. Ellos buscan un taxi delante del cine, pero es mejor buscarlo en la esquina.
4. Manuel no quiere empezar su trabajo hasta el lunes. Su jefe prefiere que lo empiece mañana.
5. José dice que va a traerme el cheque esta noche, pero no es necesario que me lo traiga hasta mañana.
Explanation:
Pronominal verbs relate to a pronoun, so they require a reflexive pronoun. In questions 1 and 5, there are two object pronouns, so it is used the RID order (Reflexive - indirect - direct). An indirect object is the person or thing for whom an action is being or has been performed. On the other hand, direct object pronouns stand in for nouns when it is clear who or what is being talked about. In question 4, it is only used the Reflexive direct pronoun.
For questions 2 and 3 there are no reflexive pronouns because of the structure of the sentence (you can notice that there is no word "que" before the blank).