“有志者，事竞成，破釜沉舟，百二秦关终属楚；苦心人，天不负，卧薪尝胆，三千越甲可吞吴。”这句话给我们  的启示是（    ）

①人生要树立远大理想           ②只要有理想就能取得成功

③实现理想要矢志不移           ④实现理想离不开艰苦奋斗

    I have two pen ____. They ____ Zhang Ming and Zhao Ping. Zhang Ming is ____ Shanghai. Zhao Ping is in Beijing. We like ____. We are all in sports clubs(俱乐部) at school. I ____ play basketball. Zhang Ming likes ____. And Zhao Ping often ____ ping-pong. ____ we like different(不同的) food. I like vegetables. Zhang Ming likes ____ hamburgers and Zhao Ping eats lots of fruit every ____.

尿素化学式CO（NH₂）₂等植物营养物质过多进入水体会恶化水质，导致“水华”现象．尿素属于（  ）