今年汉翔题目请版上高手解惑，谢谢。
祝大家考试顺利，金榜题名!
12. ____ razor-thin profit margins, running a successful restaurant can seem more like a magic than a money-making Enterprise.
(1) Because (2) Because of (3) Because that (4) Because with
14. For a social worker who has dedicated his entire life, this acknowledgement is long ____.
(1) due (2) over (3) overdue (4) due over
16. After ____ 15 pounds, John learned that he can't eat everything he wanted just because he's in marathon training.
(1) gains (2) being gained (3) having gained
(4) he was gaining
17. A 2013 poll in the country revealed that 10 percent of respondents ____ an injury in their bathrooms.
(1) suffers (2) had suffered (3) was suffering (4) had been suffering
20. The problem with unconventional currency is all the trust ____ to make it work, said economist.
(1) require (2) to require (3) that is required
(4) which requires it