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26题的答案是（ ）
A、long
B、short
C、happy
D、sad
【正确答案】：A
【题目解析】：在第26题中，句子提到“Habitat destruction can be...or it can be subtle, occurring over a...period of time without being noticed.”，这里的“subtle”表示“微妙的、不易察觉的”，因此与之相对的是明显或显著的变化，而这样的变化往往需要较长的时间才能被察觉。因此，正确的形容词应该描述一个相对较长的时间段。 选项A "long" 表示“长的”，与句意相符，表示栖息地破坏可能是微妙的，发生在一段不被注意的长时间内。 选项B "short" 表示“短的”，与句意不符，因为如果是短时间内的变化，通常不会是微妙的，而更容易被察觉。 选项C "happy" 和选项D "sad" 是情感形容词，与描述时间长度无关，因此不符合语境。 因此，正确答案是A，即“long”。