write two complete sentences in the preterit, using the words provided. For sentence a, use the indirect object pronoun and the direct object pronoun

Clarification:

I found the complete exercise online:

Write two complete sentences in the preterit, using the words provided. For sentence a, use the indirect  object pronoun and the direct object pronoun. Then, for sentence b, rewrite the sentence using double  object pronouns. Follow the model.

MODELO: yo / dar / (a ti) / mi tarjeta de credito.

a. Yo te di mi tarjeta de credito.

b. Yo te la di.

1) Mario / prestar / (a su hermano) / un sueter.

2) tu / pedir / (a mi) / dinero

3) yo / buscar / (a mi madre) / unas zapatillas azules

4) mi hermana / regalar / (a nuestro padre) / una bata nueva

5) nosotros / dar / (a nuestros amigos) / regalos especiales

1. a. Mario le prestó a su hermano un suéter.

b. Mario se lo prestó.

2. a. Tú me pediste dinero.

b. Tú me lo pediste.

3. a. Yo le busqué a mi madre unas zapatillas azules.

b. Yo se las busqué.

4. a. Mi hermana le regaló a nuestro padre una bata nueva.

b. Mi hermana se la regaló.

5. a. Nosotros le dimos a nuestros amigos regalos especiales.

b. Nosotros se los dimos.

Explanation:

To complete this exercise, you have to write sentences in the Spanish preterite tense ("pretérito perfecto simple" in Spanish), which is used to talk about actions completed at some point in the past.

For sentences "a", you have to use direct object pronouns and indirect object pronouns.

On one hand, direct object pronouns (''pronombres de objeto directo'' in Spanish) are used when you want to replace a direct object, which is a noun, so you do not have to repeat the noun.

On the other hand, indirect object pronouns (''pronombres de objeto indirecto'' in Spanish) are used when you want to say to whom or for whom something is done.

For sentences "b", you have to use double object pronouns (''pronombres de doble objeto'' in Spanish), which means that both an indirect object pronoun and direct object pronoun are used in the sentence.  You change the objects for the pronouns: for example, in question 1: "Mario se lo prestó" (es decir, le prestó el suéter a su hermano).

(a) The relationship between wavelength , frequency f and velocity v of a wave is

For the sound wave of our problem, the frequency is  while the velocity is , so its wavelength is 


(b) The only difference here is the velocity, because the speed of an electromagnetic wave is equal to the speed of light:

So, if we use the wavelength we found in the previous part, we get the frequency of the electromagnetic wave