HELP pls i am stuck on these conjugations

Okay so i'm taking an online spanish course (penn foster), and in the study guide, you have to create a bunch of sentences with words you've learned so far. translating, reading, and those kinds of things are fairly easy, but when it comes to making my own sentences, my brain just kinda waltz's away. anyone got any tips?

No debemos el medio ambiente. a. contaminar b. preservar c. desechar d. cumplir

Decide if the following definite article and noun agreement is correct or incorrect. el calendario correct incorrect