洪港的李爷爷今年70多岁了,他经常讲一些“爷爷过去的事情”,其中不可信的事情是:( )
请你参与某历史兴趣小组“学习借鉴国外先进经验"的研习活动。
— I am sorry to tell you that you failed the exam.
— Well. I've already known it.
下列属于特异性免疫的是( )