Homework:

Why is it important to prepare for a job interview?

The reason why the preparation of a job interview is important is the way to success to get the job.
At the interview, most of people can be nerves wracking =  nerve-wracking, and this feeling can affect you doing = to have an unusual attitude or forget what they want to mention.
To stay clam = calm at the interview, I am quite sure that previously practiced preparation of = for a job interview will be effective and helpful to show the interviewer good = a good  first impression and proofs = prove you are a competent applicator = applicant.

Thank you for a very well said answer, Haemin!