The Great Barrier Reef is the earth's largest reef system. At a length of over 2,500 km it is the largest (26)____________ structure. You can even see it from space. However, the reef is in danger of dying . Because of global (27)_________,
the temperaturebin the atmosphere keeps rising. This also affects the water temperature. When the oceans get too warm the colourful reefs (28)__________ grey and die. The reef is also dying from pollution caused by factories on the Australian and  Indonesian coasts
It's a pity that we don't (29)___________ the environment the ways the Aborigines did thousands of years ago. They respected nature, the animals and plants around them. They never killed more animals than they could eat. (30)________ , when Europeans arrived the Australia they destroyed a lot of things that the Aborgines valued
26. A.living           B.alive             C.live               D.life
27. A.cooling        B.heating         C.warming       D.changing
28. A.make           B.turn              C.get                D.come
29. A.take care     B.look at          C.make for       D.care about
30. A. Although     B. Moreover    C. Therefore     D. However