18.
A. Failure to keep a promise
B. Lack of frankness
C. Feelings of betrayal
D. Loss of contact
19.[音频]
Along the low-lying Colorado River
B. At the Dinosaur National Monument
C. Along the border of the U.and Canada
D. At museums of natural history in large cities
20.
A. Volcanic explosions could bring whole animal species to extinction
B. Some natural disaster killed a whole herd of dinosaurs in the area
C. The pit should be carefully preserved for the study of dinosaurs
D. The whole region must have been struck by a devastating flood
21.
A. They floated down an eastward flowing river
B. They lay buried deep in the sand for millions of years
C. They skeletons of dinosaurs inhabiting the locality
D. They were remains of dinosaurs killed in a volcanic explosion
22.[音频]
A. Indulging in seeking leisure and material comfort
B. Attaching too much importance to independence
C. Failing to care for parents in the traditional way
D. Leaving their parents on the verge of starvation
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