1．unprotected adj.未采取保护措施的，无防护的

　　[教材原句]　The virus is spread in three ways-it can be passed on through unprotected sex, through blood and from a mother to her child.

　　这种病毒通过三种方式传播--它可以通过没有防护措施的性行为、血液及母婴传播。

　　①As much as 40 percent of unprotected crops have been destroyed.

　　没有采取保护措施的庄稼被损毁的多达40%。

　　(1)protection n．　　　　　 保护；保障；抵御；防卫

　　under protection 受保护

　　(2)protect vt. 保护

　　protect... from/against 保护......不受......侵害

　　(3)protective adj. 保护的；防护的

　　②They traveled under the protection of a number of soldiers.

　　他们在一些士兵的护卫下旅行。

　　③The plants should be protected from/against the cold.

　　应该保护这些植物使之不受冻。

　　[即境活用1]　用protect的适当形式填空

　　①Her thin coat gave/provided little protection against the cold.

　　②He's very protective towards his sister.

　　2. burst on the scene突然出现

　　[教材原句]　However, since the disease burst on the scene in the 1980s, it has become a serious problem around the world.

　　但是，自从艾滋病在20世纪80年代突然爆发以来，它已经成为一个严重的全球性问题。

　　①Various computer games burst on the scene during the Internet boom.

　　在互联网热潮时期，各种各样的电脑游戏出现了。

　　on the scene　　　　　　　　　 当场，在现场

　　come/appear/arrive on the scene 到场

　　behind the scenes 秘密地，在幕后，不公开的

②It was not long before a helicopter arrived on the scene to rescue the survivors of the plane crash.