1. Totally without light and subjected to intense pressures hundreds of times greater than at the Earth’s surface，the deep—ocean bottom is a hostile environment to humans，in some ways as forbidding and remote as the void of outer space.
2.Basic to any understanding of Canada in the 20 years after the Second World War is the country’s impressive population growth.
3.As a result，claims that eating a diet consisting entirely of organically grown foods prevents or cures disease or provides other benefits to health have become widely publicized and form the basis for folklore.
4.There are numerous unsubstantiated reports that natural vitamins are superior to synthetic ones， that fertilized eggs are nutritionally superior to unfertilized eggs，that untreated grains are better than fumigated grains and the like.
5. The desperate plight of the South has eclipsed the fact that reconstruction had to be undertaken also in the North，though less spectacularly.
6·The new accessibility of land around the periphery of almost every major city sparked an explosion of real estate development and fueled what we now know as urban sprawl.
7.But these factors do not account for the interesting question of how there came to be such a concentration of pregnant ichthyosaurs in a particular place very close to their time of giving birth.
8. Amid rumors that there were prehistoric mammoths wandering around the unknown region and that somewhere in its wilds was a mountain of rock salt 80 by 45 miles in extent，the two captains set out.
9. In the seventeenth century the organ, the clavichord，and the harpsichord became the chief instruments of the keyboard group，a supremacy they maintained until the piano supplanted them at the end of the eighteenth century.
10.A series of mechanical improvements continuing well into the nineteenth century, including the introduction of pedals to sustain tone or to soften it, the perfection of a metal frame and steel wire of the finest quality，finally produced an instrument capable of myriad tonal effects from the most delicate harmonies to an almost orchestral fullness of sound，from a liquid，singing tone to a sharp, percussive brilliance.