The destruction of habitats(栖息地)all over the world is the primar

The destruction of habitats(栖息地)all over the world is the primary reason species are?becoming extinct(灭绝)or endangered．Houses,highways,dams,industrial buildings,and?ever-spreading farms now dominate?21?formerly occupied by forests,deserts,and wetlands．22?the beginning of European settlement in America,23, over 65,000,000 acres of?wetlands have been drained．One million acres alone vanished 24?1985 and 1995． Habitat destruction can be?25?or it can be subtle,occurring over a 26?period of time?without being noticed．27?such as sewage from cities and chemical runoff fromfarms,can change?the?28?and quantity of water in streams and rivers．To?29?living in a delicately balanced?habitat,this disturbance can be as 30?as the clear-cutting of a rainforest． 31?remaining habitats are carved into smaller and smaller pockets or islands,remaining?species are forced to exist in these?32?areas,which causes further habitat?33?These?species become less adaptable to environmental?34；in fact,they become?35?endangered．Scientists believe that when a habitat is cut by 90%,one-half of its plants,animals and insects will?become extinct． 第23题的答案是（ ）
A、for example
B、in addition
C、at last
D、after all
【正确答案】：A
【题目解析】：第23题出现在文本的第二段第一句，需要填入的词应该能够引导一个例子，来说明“栖息地破坏”的程度或严重性。 A选项“for example”意为“例如”，用于举例说明某个观点或情况，符合语境。 B选项“in addition”意为“另外”，用于补充信息，但此处需要的是一个举例的词语，而不是补充信息。 C选项“at last”意为“最后”，通常用于表示时间或顺序上的最后一点，不适用于此处。 D选项“after all”意为“毕竟”，常用于表示对某个观点或情况的强调或总结，也不符合此处的语境。 根据上下文，句子“over 65,000,000 acres of wetlands have been drained”是一个具体的数据，用于说明栖息地破坏的严重性，因此“for example”是最合适的选项，用于引出这个具体的例子。因此，答案是A。