One of the most interesting new books published recently is "Spaceship" by Prof. E.C. Walker. Our earth he says 61. (a) is /(b) have been (c)/ will be like a spaceship, and all the 400 million people 62. (a) over/ (b) on /(c) upon earth are passengers on it. And we are heading 63. (a) about /(b) to /(c) towards a disaster. The levels of atmospheric pollution 64. (a) increasing/ (b) arriving/ (c) coming in the cities and industrial areas of the world could in time change the weather patterns of the earth, raising the temperature 65. (a) in /(b) of /(c) for the whole planet. If this rose a few 66. (a) degrees /(b) steps /(c) miles the deserts of the world would expand to double their size. The polar ice caps would start melting. If the polar ice caps melted, the 67. (a) water/ (b) ice /(c) sea level all over the world would rise 68. (a) in/ (b) by/ (c) to about 60 meters. Prof. Walker's 69. (a) idea /(b) thought /(c) book is not at all about gloom and doom. He admits that the 70. (a) ideas/ (b) solutions /(c) changes he describes could take thousands of years.