Enter the word that best completes the sentence.
word bank
straits sheer obstinate
rumor agonize luxurious
i knew my cousin would
over the news all night, so i saved her the worry and didn’t tell her.

I knew my cousin would agonize over the news all night, so I saved her the worry and didn't tell her. 
The reason your answer is agonize is because, to agonize is to be distraught while thinking of something, so by saving her the worry her cousin had no reason to agonize the news or situation. 
I hope this helps! 

Acquiring english is a way of learning where you learn english by birth, this includes listening to your parents, brothers and sisters and on the whole learning it from the environment around you while mastering standard english need qualified institutes and teachers who make certain programs and syllabus to you master the standard english. this also can include a long session of academic studies before you can master the standard english.standard english is necessary for literary works, official usage and writing materials for standardized publications or when someone needs to speak publicly. in most cases the employers of a company also demand and like the use of standard english from their employees.