【已刪除】16. (A) therefore (B) henceforth (C) whereas (D) once
Passage A
Amphibians help maintain the balance of nature: sometimes because they are food for other animals, including humans;
other times because they eat large amounts of insect pests and larvae. However, amphibians are disappearing from areas where
they __16__ were common. People’s activities appear to be the main cause of this __17__ . Habitats are destroyed as marshes
and other wetlands are drained; forests are cut down; home, roads, and other __18__ are built. In many places, amphibians are
run over by cars as they cross the roads built between their homes and their spawning grounds. Chemical substances from acid
rain and pesticides also harm amphibians when they are absorbed through their moist skin.
As their important contributions have been recognized, efforts have been made to protect them. Measures __19__ by
some countries that protect the environment from the harmful effects of acid rain and the misuse of pesticides also help protect
amphibians. Countries, such as India, have banned the export of frog legs ( __20__ a delicacy in some parts of the world). In
many parts of Europe, toad tunnels have been built to help toads safely cross the roads that block their travel to spawning
grounds.