如图是甲、乙两种物质的溶解度曲线，根据图中信息填空：

（1）t₁℃时，甲、乙两种物质的饱和溶液的质量分数____ （选填“相等”或“不相等”）．

（2）t₂℃时，甲、乙两种物质的溶解度大小关系：甲____ 乙（填“＞”、“＜”或“=”）

（3）当甲中含有少量乙时，可以用____ 法提纯甲．

（4）要使t₁℃时甲的饱和溶液变成不饱和溶液的方法有____ （任填一种即可）．

（5）t₁℃时，往100g水中加入60g甲，充分搅拌后得到甲的饱和溶液的质量是____ 克．

    Hello! My name is Kim. I'm from the U. S. I am a tall girl. I like basketball best. I often play basketball with my friends on the playground. We have two teams—the White Team and the Yellow Team. I am on the Yellow Team. Each team has five players. My favourite basketball player is Yao Ming. I like him best and I want to be a basketball player like him.

中国篮球运动赛程增加，参赛队伍增加，CBA对裁判工作的要求越来越高，裁判要遵守全新的篮球规则，以应对篮球运动的不断发展。下列说法正确的是（   ） 

把命题“对顶角相等”改写成“如果…那么…”的形式：​ ____