题目

In the sea there are many islands . In its warm waters there are some little ones. We call them “Coral Islands”  .    A coral island is very nice to look at .  It looks like a ring of land with tress ,  grass , and flowers on it . One part of the ring is open to the water .  There is a little round lake inside the island .    If you look into this lake , you will see beautiful coral . You may think they are flowers.    If you look at a piece of coral , you will see many little holes in it . In each of these holes a very small sea animal has lived . These sea animals make t酚酞是一种______________，微溶于______________，易溶于______________。酚酞——酒精溶液常用作______________，遇酸为____，遇碱为______________。