阅读理解。
Plants that live in the rainforest have adapted in amazing ways to several very difficult conditions．
This means that the plant has changed something in its "body" or "habits" to make it easier to survive
in difficult conditions．There are several conditions they have had to adapt to．First,the soil of the
forest floor is shallow．Also,the soil of the rainforest is not very rich,or easy to grow in．Next is the
problem of very heavy rain which continues over a large part of the year．Finally,many plants of the
rainforest are food for animals that live there．
The biggest problem that rainforest plants have to adapt to is the lack of sunlight in the rainforest's
lower levels．Plants have adapted to this problem in several ways．Many plants have very large
leaves．The large leaf is helpful because it has a bigger surface area．The bigger surface area a leaf
has,the more sunlight it can absorb．The canopy trees adapt by growing to be 100 feet tall so that
their leaves can grab all available sunlight．Other plants called lianas (climbing woody vines) have
adapted by rooting themselves in the soil of the forest floor and growing up the trees until they reach
the canopy layer．Still other plants,such as epiphytes,have adapted by growing directly on the trees'
trunks and branches in the canopy and understory layers of the rainforest．
An adaptation to the large amounts of rainfall that many rainforest plants have is called "drip tips"．
Their leaves are tapered (逐渐变细) to a sharp point at the end．This allows water to run off the
leaf quickly．There are many other adaptations that rainforest plants have made to their environment．
These will be discussed in detail,as we investigate the plants of the rainforest!
1．Which of the following is a difficulty that the rainforest plants have to face?
A．Changes in their "body" or "habits"．
B．Soil that is not very deep．
C．Epiphytes that grow on trees' trunks．
D．The worsening of the natural environment．
2．How do lianas adapt to the environment in the rainforest?
A．They grow under big leaves for protection．
B．They rely on other plants to reach the canopy layer．
C．They change their leaf structure constantly．
D．They grow on other plants' branches．
3．The underlined word "This" in Para．3 probably refers to ________．
A．the takein of sunlight
B．the large amounts of rainfall
C．the leaves' having a sharp point at the end
D．water's running off the leaves quickly
4．What can be inferred about rainforest plants?
A．They have to face dangers not only from animals but also from each other．
B．Too little sunlight and too much water are the biggest problems they face．
C．Different kinds of plants have different ways to absorb sunlight．
D．All of their adaptations have been investigated in detail．
5．What would be the best title of the passage?
A．How Do Plants Adapt to the Rainforests?
B．Why Do Plants Change Themselves?
C．What Kind of Plants Is the Most Adaptable?
D．What Is the Best Place for Plants to Live in?
