[不定项选择题]共用题干 第二篇

Natural Medicines

Since earliest days,humans have used some kinds of medicines.We know this because humans have
survived.Ancient treatments for injury and disease were successful enough to keep humans from dying out
completely.
They were successful long before the time of modern medicine.Before the time of doctors with white
coats and shiny（发亮的）instruments. Before the time of big hospitals with strange and wonderful equipment.
Many parts of the world still do not have university-educated doctors. Nor do they have expensive hospi-
tals.Yet injuries are treated.And diseases are often cured.How?By ancient methods.By medicines that
might seem mysterious , even magical（有魔力的）.Traditional medicines are neither mysterious nor magical,
however.
Through the centuries, tribal（部族的）medicine men experimented with plants. They found many use-
ful chemicals in the plants.And scientists believe many of these traditional medicines may provide the cure
for some of today's most serious diseases.
Experts say almost 80% of the people in the world use plants for health care.These natural medicines
are used not just because people have no other form of treatment.They are used because people trust them.
In developed areas,few people think about the source of the medicines they buy in a store.Yet many wide-
ly-used medicines are from ancient sources,especially plants.Some experts say more than 25% of modern
medicines come,in one way or another,from nature.
Scientists have long known that nature is really a chemical factory.All living things contain chemicals
that help them survive.So scientists' interest in traditional medicine is not new.But it has become an ur-
gent concern.This is because the earth's supply of natural medicines may be dropping rapidly. It can be seen from the passage that the earth's supply of natural medicines________.
A.may never be exhausted
B.may be dropping rapidly
C.is surprisingly big
D.is as rich as ever