阅读理解。
Sandstorms (沙尘暴) happen suddenly and have effects on large areas. One example was a sandstorm on the Western Route. It moved quickly southward (向南 ) from May 4th to 6th,1993,having effects on a total area of l.1 million sq km,from northern Xinjiang to the Hexi area of Gansu,western Inner Mongolia and most of the Ningxia Hui Autonomous Region. The wind speed reached 37. 9 m/s, and the visibility (可见度) was less than 50m. In Xinjiang,Gansu,Inner Mongolia and Ningx-ia,85 persons died and 264 were injured;4,412 houses were damaged,and 120,000 animals died or went missing. The direct economic losses (直接的经济) were about 550 million yuan,which further damaged the environment and economic development. Another example was the sandstorm which happened from April 16th to 18th,1998. Blowing from west to east,it even reached the lower reaches of the Yangtze River. This never happened in hisl.ory. A sandstorm meeting rain over Beijing formed " muddy(多泥的 ) rain" there. Floating dust troubled the Inner Mongolia Autonomous Region, Beijing, Ji'nan of Shandong Province and Nanjing.
1. How many areas did the sandstorm in 1993 have effects on?
A. Three.
B. Four.
C. Five.
D. Six.
2. persons were injured in the sandstorm in 1993.
A. 85
B. 264
C. 4,412
D. 120,000
3. The sandstorm in 1998 started blowing from .
A. east
B. south
C. west
D, north
4. Which of the following is true according to the article?
A. The sandstorm in 1998 lasted three days.
B. Sandstorms just happen in the west of China.
C. Sandstorms like the one in 1993 never happened in history.
D. A person could see the building 100 meters far from him in the sandstorm in 1993.
畸形通常采取何种矫治方法（）