Some plants get so hungry they eat flies, spiders, and even small frogs. What's more amazing is that these plants occur naturally (in special environments) in every state. In fact, they're found on every continent except Antarctica. You've probably seen a Venus' flytrap. It's often sold in museum gift stores, department stores, and even supermarkets. A small plant, it grows 6 to 8 inches tall in a container. At the end of its stalks(茎)are specially modified leaves that act like traps. Inside each trap is a lining of tiny trigger(触发)hairs. When an insect lands on them, the trap suddenly shut. Over the course of a week or so, the plant feeds on its catch.
; c F8 P/ e0 S4 R0 X The Venus' flytrap is just one of more than 500 species of meat-eating plants, says Barry Meyers-Rice, the editor of the International Carnivorous Plant Society's Newsletter. Note: Despite any science-fiction stories(科幻小说)you might have read, no meat-eating plant does any danger to humans.$ f1 y8 a2 Z) K* Z+ j( ]" ^* y
Dr. Meyers-Rice says a plant is meat-eating, only if it does all four of the following: "attract, kill, digest, and absorb" some form of insects , including flies, butterflies, and moths. Meat-eating plants look and act like other green plants—well, most of the time.
4 R! V2 k: S0 Q9 q All green plants make sugar through a process called photosynthesis(光合作用). Plants use the sugar to make food. What makes "meat-eating" plants different is their bug-catching leaves. They need insects for one reason: nitrogen(氮). Nitrogen is a nutrient that they can't obtain any other way. Why Almost all green plants on our planet get nitrogen from the soil"Meat-eating" plants can't. They live in places where nutrients are hard or almost impossible to get from the soil because of its acidity(酸度). So they've come to rely on getting nitrogen from insects and small animals. In fact, nutrient-rich soil is poisonous to "meat-eating" plants. Never fertilize(施肥)them! But don't worry, either, if they never seem to catch any insects. They can survive, but they'll grow very slowly.7 D+ e7 r7 j1 }$ y
Questions 1 to 5 are based on the passage above.7 C9 y6 ~# g- f0 m
1.According to the passage,carnivorous plants_____.* J. @" x8 y! h6 T& l7 l3 {
A.only grow in wild filed B.are rare to see/ j: z' [3 Q, ^" a' X- E$ Y" T
C.are as common as flies D.cannot grow on Antarctica
?8 \9 H, m- _ 2.Venus'flytrap preys on insects by_____.
3 G& W. u( n1 L- h. i A.its numerous elongated stalks B.a container where it grows
! ~+ ]* B5 W$ i: M! j C.its insect-catching leaves D.the lining of tiny trigger hairs0 L# ]6 H: p& l4 }4 o( C
3.We can conclude from the third paragraph that_____.
7 b4 B% S7 h+ Z/ R% C0 M+ u$ X9 u A.carnivorous plants are dangerous
# q7 S4 m6 v% K6 p B.carnivorous plants are fictional
5 _% Z# v# a+ z" q2 H2 c8 R3 x" C& K0 U C.carnivorous plants occasionally eat books0 X8 E! u, y' i
D.carnivorous plants are harmless to humans- Z ^# v3 Q' L' ~7 B/ R8 x
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发表于 2012-8-14 10:30:44
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