If you go out to the fields at night in spring or summer, you can hear frogs singing 1.__ (joy) here and there. It seems as if they were performing a field symphony.

The frog is a good and useful creature that benefits human beings. They can catch fast-moving insects. Each frog eats a large number of pests that are harmful _2.__ crops. This little creature is regarded __3._ “the natural enemy of pests”．

4._ now frogs are getting fewer and fewer. This is because they are killed and put on the table as a delicious dish by their chief enemy, human beings. It is __5.__ shameless and cruel act, isn’ t it？_6._ cause responsible for the rapid reduction of frogs is that farmers use insecticides (杀虫剂) to kill pests and frogs get killed as a result of drinking poisoned water __7._ eating poison-killed insects.

Something must be done without delay _8._(save) frogs. If we don’t punish those __9._ sell and kill frogs to make money, then one day all of us __10.__(punish) by nature for failing to keep the balance of nature.