Most academic essays use tense of verbs. a. simple past b. past perfect c. present simple d. present progressive

they use simple past tense

i think the answer would mist likely be an adjective clause, because unhappy is an adjective.

#1  sara was always tasked with selecting birthday presents for her friends and family because everyone admired her  impeccable taste. 

impeccable (adj): perfect, flawless

#2  they moved to the united states many years ago, but their  insular  attitudes made it difficult for them to socialize. 

insular (adj): isolated; separate

#3  the professor explained the  semantic  relationship between the two nouns used in the sentence. 

semantic (adj): related to words or the meanings of words 

happy to : )