The huge explosion at Krakatau was the result of two different factors. One was that the v

The huge explosion at Krakatau was the result of two different factors. One was that the volcano had not broken out for some time and so at the very center of the volcano there was an huge plug of lava, this acted like a cork(塞子) in a bottle, stopping the pressure below from being released(释放). The second factor was that ocean water entered the very centre of the volcano as the explosions became more violent. This caused superheated steam to build up enormous pressure and this was finally released in the largest explosion of all on August 27, 1883. The sudden release of the pressure sent huge amounts of ash, rock and dust into the sky. Some of the ash rose 80km into the air and traveled around the Earth causing brightly coloured sunsets for several years.
Krakatau almost disappeared; for many years after this explosion, it remained very quiet. However, there was still activity going on under the sea and on 25 January, 1925, a small volcanic cone appeared above the surface of the water. This new volcano was named Anak Kmkatau, or Child of Krakatau. Over the following years, the size of the island grew larger, by 1959, the island was 300 metres above the surface of the sea. The volcanic activity has continued and the latest eruptions were in 1995.
There is no doubt Krakatar will continue to grow and there is also strong evidence that at some point in the future there will be another violent explosion. Krakatau is in a part of the world where the surface of the Earth is unstable and is always moving and cracking. If, in the future, another “cork” bees fixed in the centre of the volcano, the pressure will build up. A series of a smaller explosions will allow sea-water into the centre of the volcano and once again the result will a terribly destructive explosion.
66. The latest eruptions were in    .
A.1925           B. 1959           C. 1995          D. 1983
67. The pressure under the volcano can not be released because     
the plug looks like a cork in a bottle
the volcano hasn’t broken out for some time
the center of the volcano is blocked(堵塞) by lava
the temperature of the steam is not high enough.
68. We can infer from the article that Krakatau volcano    
A. has broken out three times               B. never dies but continues to be active
C. will kill many people again in the future    D. is always moving and growing above sea.
69. All of the following results are caused by the explosion at Krakatau EXCEPT that    
A. ash, rock and dust was thrown high into the air
B. others small volcanoes were soon produced.
C. The island of Kratau was destroyed
D. People saw beautiful sunsets for some years
70. The article is mainly about    
A. the cause of the Krakatau volcano      B. the danger of the Krakatau volcano
C. the history of the Krakatau volcano     D. the future of the Krakatau volcanoC