4문제 정도 모르겠어요 ㅠ.ㅠ

우선 p 115 쪽

10.The head office must send the approval slip for Mr.Reynolds start working with us

에서 답이 start 를 to start로 고치는건데 왜 이렇게 되나요.?

p117 쪽

18번 A notice about our annual system upgrade______on the company bulletin board,

detailing what steps should be performed by next week.

a. posts b.posted  c.to be posted  d. was posted

답은 d 에요

21.three people form the reseach department have been asked to investigate ways

_____non-taxable imported goods into the country.

a.bring  b.of bring  c.to bring  d.bringing

답은 c

24.I have enclosed two reference letters,and I hope that this will serve_______my credentials.

a.to verify b.to verifying c.to be verifying d.to verification

답은 a

 질문이 많죠.?제가 토익 초짜라서요 ㅠ.ㅠ

이렇게 4문제 모르겠네요.해설지에 왜 이게 답인지 자세히 설명이 안되어 있어서

질문올려요..자세히 누가 설명좀 해주세요~~~~~~~~~~~~~~~~~