cetron 基本例句 n.塞特龙 The central question is how many mild cases Mexico has had, Dr. Martin S. Cetron, director of global migration and quarantine for the Centers for Disease Control, said in an interview. 核心问题是墨西哥到底有多少疑似病例，这是疾病防控中心国际移民检疫局的部长马丁博士在一次采访中提到的。 dltcedu