【题目】The health security systems of many countries are undergoing considerable ______.
A.reservationB.transformationC.distinctionD.submission
在线课程【答案】B
【解析】
考查名词词义辨析。句意：许多国家的卫生安全系统正在经历重大变革。A. reservation预订；B. transformation改革，变革；C. distinction区别；D. submission提交。根据前文The health security systems可知，此处指“卫生安全系统的变革”。故选B。