Did I fill in the blanks correctly?

Question

Can someone check this exercise problem I did? (I have no way to know if I did it right or not)

Fill in the blanks with words from the box. caminamos química trimestre detrás regresar

(1) ANA: Pedro, gracias por ____ al laboratorio conmigo.

PEDRO: De nada, Ana.

(2) ANA: ¿Éste es el laboratorio de ____ ?

(3) PEDRO: No, éste es el laboratorio de física. El laboratorio de química está ____ de la biblioteca.

(4) ANA: Ay, no. ¿____ a la biblioteca?

(5) PEDRO: Sí. Este ____ necesitamos trabajar mucho.

My answers:

(1) caminamos (2) química (3) detrás (4) regresar (5) trimester

I think (1) and (4) might be incorrect. Do I need to switch them? “Regresar” confuses me because it’s in the infinitive form. I’m not sure if it can be placed after “por.”

Answer 1

Hi SocialPanda

Yes you need to swap them:

1. Thank you for returning to the laboratory with me.
2. Shall we walk to the library?