根据汉语意思完成句子。（每空一词）

1.谁拆毁了这些古城墙？

Who _______ _______ the old city walls?

2.人们把黄河当作我们中 * * 的象征。

People _______ the Yellow River _______ a symbol of the Chinese nation.

3.科学家们发现这个帝王墓破旧不堪了。

Scientists found that the emperor’s tomb was _______ _______.

4.从明天起，人们开始重建家园。

From tomorrow _______, the workers are beginning to _______ their homes.

5.这座桥有六百多年的历史了。

The bridge is _______ _______ 600 years old.

简述外军有关军事应激损伤的防护研究现状。