Final answer:
The correct verb form is 'hacía'
Step-by-step explanation:
The correct verb form to complete the sentence is hacía.
Example: Yo hacía calor todo el verano.
In this sentence, the verb form 'hacía' is the correct form of the verb 'hacer' (to do/make) in the past tense. It matches the subject 'yo' (I) and indicates ongoing action in the past.
Learn more about Spanish verb forms