评论
打印
1.Who believes the Sahara desert is a lot older than we thought?
a) writers
b) scientists
c) travellers
d) nomads
2.In which country is the centre that did the research?
a) Chad
b) Peru
c) Sudan
d) Norway
3.What did scientists use to work out the age of the Sahara?
a) carbon dating
b) a magnifying glass
c) computers
d) satellites
4.What became less frequent in African summers 7 million years ago?
a) monsoons
b) visiting dinosaurs
c) heat waves
d) sand storms
5.What formed in Chad that started the Sahara desert?
a) a village
b) sand dunes
c) a river
d) a giant rock
6.How much of Africa does the Sahara cover?
a) 10%
b) 15%
c) 20%
d) 25%
7.How far does the Sahara go to the east?
a) to Kenya
b) to the Indian Ocean
c) to the Red Sea
d) to the Nile river
8.What kind of evidence does Stefan Kröpelin want to see?
a) geological evidence
b) geographical evidence
c) geometric evidence
d) geothermal evidence
9.What did Stefan Kröpelin say the research is based on?
a) guesswork
b) geology
c) sand
d) numbers
10.How far back does our knowledge of the Saharan climate go?
a) 10,000 millennia
b) 10,000 weeks
c) 10,000 years
d) 10,000 centuries
