计算：-4+7-4=____ ．

简单地说，环境人口容量就是指（    ）

我会组词。

祸____        妨____        绞____       愧____

锅____        防____        校____       槐____

阅读下面两则材料，完成后面的填空。
【材料一】
某市学龄儿童生活习惯调查统计表

【材料二】
    调查显示，高血压、糖尿病、血脂异常、超重与肥胖等成年期慢性非传染性疾病正在低龄化，逐渐成为威胁城市儿童少年健康的突出问题。l5至17岁少年高血压患病率高迭7.0％，学龄儿童血脂异常率为2.2％，l3至l7岁少年糖尿病患病率为3.6‰。在包括高血压、肥胖、血脂异常等一系列代谢异常指标的“代谢综合征”控制中，有64．1％的孩子至少有一项指标异常。
——《中国学龄儿童少年营养与健康状况调查报告》
    从以上两则材料中可以得出如下结论：锻炼时间____、饮食结构____、____ 的娱乐习惯等原因造成成年期慢性非传染性疾病低龄化，有____ (填百分数)的儿童“代谢综合征”指标异常。

根据短文内容，用方框中所给单词的适当形式填空，每词限用一次。                                                                                     

happy    buy    alone   pet    easy

    Do you love animals? Would you like to keep animals as a pet? Nowadays, many people like to keep pets at home. The most popular____  are cats and dogs. They are friendly to people, and they are also ____  to take care of. Some people like parrots as pets. Pets lovers will____ lots of things for their pets, such as beds, clothes and even toothbrushes. Pets are very useful, too. The people who can’t hear need the dogs' help to answer the door. And the people who live____  should keep a pet if he wants to be healthier and ____ . If you have pets, don't forget to spend more time with them. They need love, too.