The word hallmark in paragraph 4 is closest in meaning to
A. characteristic
B. problem
C. disadvantage
D. experiment
查看答案
The phrase set eyes on in paragraph 2 is closest in meaning to
A. colonize
B. observe
C. imagine
D. explore
All of the following were discovered at L'Anse aux Meadows EXCEPT
A. wild grapes
B. huts made of sod
C. sewing tools
D. an iron forge
In what way is salinization a serious problem for agriculture？
A. Soils with high salt concentrations are destructive to crop plants．
B. Salinization can lead to soil compaction or to LOSS of soil cover．
C. Excessive amounts of water are required to prevent salinization．
D. Adding salt to fertilizer raises the operating costs of agriculture．
人类掠夺式的开发造成生态环境破坏是生物灭绝和濒危的主要原因。 [ ]
A. 正确
B. 错误
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