皮皮有一个装有黄、蓝、绿、红四种颜色的球的袋子，其中25％是绿色的球，10％是黄色的球，余下的球中20％是蓝色的，如果蓝色的球有13个，那么红色的球有____个。

“你能做到的，比你想象的更多。”这句谚语说明（    ）

感恩感人 
黄轲——一个生命就要走到尽头而只有十六岁的男孩，为了对他进行过帮助的人说声谢谢，而不顾自己的身体已经进入倒计时和父亲踏上了“感恩之旅”。疾病早已剥夺了他站或坐的能力。每天，父亲必须小心翼翼地把他抱上轮椅，用绳子仔细地“固定”，以保证他不致滑落。父子俩从2003年开始走遍全国寻访素未谋面的恩人。因为没有钱，父亲用一辆三轮摩托车载着儿子黄舸走过了82个城市，行程13000多公里，向30多位当年给他们汇款的恩人当面道了谢。根据所学知识，回答： 

    I was never very neat, while my roommate Kate was extremely organized. Each of her objects had its place, but mine always hid somewhere. She even labeled(贴标签) everything. I always looked for everything. Over time, Kate got neater and I got messier. She would push my dirty clothing over, and I would lay my books on her tidy desk. We both got tired of each other.

    War broke out one evening. Kate came into the room. Soon, I heard her screaming, “Take your shoes away! Why under my bed!” Deafened, I saw my shoes flying at me. I jumped to my feet and started yelling. She yelled back louder.

    The room was filled with anger. We could not have stayed together for a single minute without a phone call. Kate answered it. From her end of the conversation, I could tell right away her grandma was seriously ill. When she hung up, she quickly crawled(爬) under her covers, weeping. Obviously, that was something she should not go through alone. All of a sudden, a warm feeling of sympathy rose up in my heart,

    Slowly, I collected the pencils, took back the books, made my bed, cleaned the socks and swept the floor, even on her side. I got so into my work that I even didn't noticed Kate had sat up. She was watching, her tears dried and her expression one of disbelief. Then, she reached out her hands to grasp mine. I looked up into her eyes. She smiled at me. “Thanks.”

    Kate and I stayed roommates for the rest of the year. We didn't always agree, but we learned the key to living together: giving in, cleaning up and holding on.