Read and w.rite．（用所给单词的适当形式填空。）

1. The Great Wall is very_____________________(old).

2. The Yellow River is___________________(short)than the Changjiang River.

3.Shanghai is ___________________(big) than Jinan.

4. This river is__________________(wide) than that one.

两汉时期，西域各族与中原的交往和联系加强了，西域归属中央 * * 开始于（ ）

A．窦固、窦宪大败北匈奴

B．张骞出使西域

C．设置西域都护

D．班超开始经营西域