Complete the following passage with the words or phrases in the box. Each can be used only once.(将下列单词或词组填入空格，每空格限填一词，每词只能填一次)

 Today I'm going to talk about rainforests. Are you  ____    with them? They're interesting and exciting places! Many kinds of the world's plants and animals live in the rainforests.

 However, rainforests are____ now---they are disappearing very fast because they are cut down or burnt every day. As a result,   ____  animals and plants are dying out.

 Maybe you have never been to a rainforest, so why should you protect them  ____  ?  Rainforests are important to everyone. They are important because the plants in the rainforests make oxygen . We need oxygen to breathe.

已知，a与b互为相反数，c与d互为倒数，求：（a+b）²⁰¹⁵﹣（a+b﹣cd）²⁰¹⁶．

当今社会，虽然人民生活水平普遍改善，但仍有一些人衣食无着、无家可归，终日漂泊在外，天桥底下、地下通道、僻静街角…是他们赖以栖身的地方，这些人通常被称为“流浪者”，这一社会弱势群体需要得到全社会的关爱．关爱流浪者（　　）