从右图中，可以获得多项与甲、乙两物质溶解度有关的信息：

（1）在t₂℃时，向50mL水中加入18g甲物质，充分溶解后可得到溶液____g，是____（选填“饱和”或“不饱和”）溶液；
（2）如甲物质中混有少量乙，可以用____方法提纯；
（3）两曲线的交点A表示____；
（4）你还能获得的一项信息是：____。

一个大池塘被正在生长的植物逐渐覆盖，每天新增的覆盖面积加倍，第9天池塘已被覆盖一半，那么大池塘全部被覆盖所需的天数是（　　）

    Come and see the India elephants and the new tigers from America. The bears are waiting to meet you, and the monkeys from China are waiting to throw（扔） things to you. The lovely dogs from Australia are waiting to laugh at you. The giraffes from Brazil are waiting to look down on you.
Tickets                             Open time
Grown-up:（成人）$2.00             9:00a.m—4:00p.m
Children :over 12 $1.00               Except（除）Friday
Under12 Free(免票)                  10:00a.m—3:00p.m
Keep the zoo clean!
Don't touch(触摸) , give good food or go near the animals!