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 ____1____
just around the next corner. The fast-growing population‘s
demand for food， they warned， would soon exceed their ____2____
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 _____3____
spots like present-day Somalia， and occasional years of
good harvests， the world‘s food crisis has remained just ____4____
around the corner. Most experts believe this can continue
even as if the population doubles by the mid-21st century， ____5____
although feeding 10 billion people will not be easy for
politics， economic and environmental reasons. Optimists _____6____
point to concrete examples of continued improvements
in yield. In Africa， by instance， improved seed， more _____7____
fertilizer and advanced growing practices have more than
double corn and wheat yields in an experiment. Elsewhere， _____8____
rice experts in the Philippines are producing a plant with few ____9____
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 ____10____
for hope.
1. being -%26gt； been
2. their -%26gt； its
此处物主代词指food，所以要用单数形式的所有格its.
3. relative -%26gt； relatively
修饰形容词（此处是过去分词形式）要用副词，所以要把relative改为relatively.
4. good -%26gt； bad / poor
从逻辑上说，应该是收成不好（bad / poor harvest）是带来粮食危机（food crisis） 的原因之一，所以应该把good改为poor或者bad.
5. as -%26gt； /
此处是表示“即使”的意思，所以应该去掉as，即even if.
6. politics -%26gt； political
Politics是名词，修饰名词reasons要用形容词。
7. by -%26gt； for
for instance“例如”是固定搭配。
8. double -%26gt； doubled
have （more than） doubled
9. few -%26gt； fewer
And连接两个对称结构，此处均比较级：fewer stems and more seeds.
10. crop -%26gt； crops
crop意为“庄稼，作物”时是可数名词，要用复数形式。