题目

They (plan) to help, butthey were too busy. 答案：【1】had planned日本大地震后，防化部队在灾区喷洒了大量消毒液，从预防传染病的角度看应属于（ ）A.控制传染源                        B.切断传播途径C.保护易感人群                      D.预防接种