可恶的病毒不断传播,禽类大批死亡。而灾难仍不肯停住脚步,甚至直接向人类宣战。不知道对手的真面目,人的免疫能力就无法发挥作用。免疫系统就像一支抵御疾病的部队,当一种病毒或者病菌袭击身体时,人体免疫系统首先要识别对方的特征,针对敌人的特征,进入工作状态,抵御敌人。发 Fearful virus continues to spread, a large number of birds died. Disaster still will not stop, or even declare war directly to mankind. Do not know the true face of opponents, human immunity can not play a role. The immune system is like a unit that defends the sickness. When a virus or germ attacks the body, the human immune system first identifies each other's characteristics and, in response to the characteristics of the enemy, enters the working state and defeats the enemy. hair