1. The rise of acquired immune deficiency syndrome (AIDS) around the earth has represented a major challenge to medical progress both in developed and in less — developed countries.
    全球艾滋病的蔓延无论在发达国家还是在欠发达国家都是对医学进步的重大挑战。

2. Acquired Immune Deficiency Syndrome (AIDS) was diagnosed in the United States in the late 1970s.
    艾滋病是20世纪70年代末在美国被发现的。

3. I´m immune to smallpox as a result of vaccination.
    我种过牛痘了, 所以对天花有免疫力.

4. I've always advocated gun control; the odd thing is I still do. It wasn't ignorance of crime statistics that previously kept me from owning a gun nor thinking I was immune to violence.
    我一贯主张控制枪支，奇怪的是我现在依然主张控制枪支。以前我没有枪，并不是因为我对有关犯罪的统计资料不了解，也不是因为我自认为可以不受暴力的袭击。