A． people find invisible diseases difficult to deal with
B． attacks by hidden enemies tend to be fatal
C． diseases with obvious signs are easy to cure
D． people tend to overlook hidden dangers caused by pesticides
参考答案D
解析:推理判断题。根据最后一段中的“Men are naturally most impressed by diseaseswhich have obvious signs，’says a wise physician，Dr．Rene Dubos，‘yet some of their wont enemiesslowly approach them unnoticed．…可知，在Dr．Rene Dubos看来，人们总是对那些有明显特征的疾病印象深刻，然而他们最可怕的敌人却在未被注意的情况下慢慢接近他们。故选D。