7、Therefore,we can conclude that what the painter wants to convey through the drawing is that tourists lacking awareness of environmental protection pose a threat to the ecological balance of the tourist attractions by leaving behind a huge amount of rubbish.

【译文】因此，我们可以得出，图画想要表达的含义是， 缺乏环境保护意识的游人通过乱扔大量垃圾给旅游景点的生态平衡造成了威胁。

【分析】本句常用于介绍完图画内容后揭示图画的深层含义，what此处引导的是一个主语从句。揭示图画含义的表达还有 The message conveyed in the picture seems to be that …；The intended meaning of the picture is that …; Obviously, it is …that the picture wants to convey …等。

8、To sum up the above argument, it is urgent to take some effective and relative measures.

【译文】综合以上论证，采取一些有效的相关措施势在必行。

【分析】本句承上启下，用于呼吁采取某些措施以制止或纠正某种情况的发生，下文会对措施一一列举。It is urgent to …还可以替换为 It is urgent that …，It is high time to…/that…。注意使用that从句时，从句谓语动词需使用虚拟语气形式。