다음 글의 밑줄 친 부분 중 어법상 옳지 않은 것은?Each night… | [기상직 9급 영어] 16년 1회차 기출문제 상세 페이지

다음 글의 밑줄 친 부분 중 어법상 옳지 않은 것은?
Each night our sleep is ① punctuated by periods of intense activity. Pulse and breathing quicken, blood pressure fluctuates, eyes ② darting back and forth beneath closed lids, and we dream. Researchers ③ have clearly mapped the physiology of rapid eye movement (REM) sleep. But the function of our dreams is still a mystery. Judging by the deluge of research reported at an international conference, ④ held recently, the solution is still elusive.

punctuated by

darting back and forth

have clearly mapped

held recently