改错练习题

　　Thomas Malthus published his “Essay on the
　　Principle of Population” almost 200 years ago. Ever since then,
　　forecasters have being warning that worldwide famine was (S1)
　　just around the next corner. The fast-growing population’s
　　demand for food, they warned, would soon exceed their (S2)
　　supply, leading to widespread food shortages and starvation.
　　But in reality, the world’s total grain harvest has risen
　　steadily over the years. Except for relative isolated trouble (S3)
　　spots like present-day Somalia, and occasional years of
　　good harvests, the world’s food crisis has remained just (S4)
　　around the corner. Most experts believe this can continue
　　even as if the population doubles by the mid-21st century, (S5)
　　although feeding 10 billion people will not be easy for
　　politics, economic and environmental reasons. Optimists (S6)
　　point to concrete examples of continued improvements
　　in yield. In Africa, by instance, improved seed, more (S7)
　　fertilizer and advanced growing practices have more than
　　double corn and wheat yields in an experiment. Elsewhere, (S8)
　　rice experts in the Philippines are producing a plant with few (S9)
　　stems and more seeds. There is no guarantee that plant
　　breeders can continue to develop new, higher-yielding
　　crop, but most researchers see their success to date as reason (S10)
　　for hope.

参考答案

　　参考答案：
　　S1. being → been
　　S2. their → its
　　S3. relative → relatively
　　S4. good → bad
　　S5. as → 去掉
　　S6. politics → political
　　S7. by → for
　　S8. double → doubled
　　S9. more → fewer
　　S10. reason → the reason