单选题
A jungle is a thick, tangled mass of tropical plant life. Low bushes, ferns, vines, and young trees grow very (1) . In fact, people often must use an ax or long knife to (2) the growth. Most (3) are found near the equator, in South America, Africa, and parts of Asia. Many people are confused by the difference (4) a tropical rain forest and a jungle. Tropical rain forests have tall trees. These prevent (5) from reaching the forest floor. A jungle, however, can grow only (6) tall trees do not block the sun. Very often, when tropical rain forests are (7) , the jungle moves in to take over the now-sunny forest floor. At different heights the jungle offers (8) kinds of plant and animal life. At ground level huge palms and ferns grow, much (9) they did in prehistoric times. Ants are the commonest (10) there. For that reason, anteaters (11) on the jungle floor. Jaguars, tapirs, armadillos, and snakes are also (12) sights in the jungle. Twenty-five feet (13) from the jungle floor, sunlight streams through trees that are alive with animal and insect life. (14) the air is always hot and humid, all life moves at an easy pace. Lizards, tree-dwelling anteaters, wild turkeys, sloth, and kinkajous, who live (15) ants and insects, can find their food very easily. To get food, they never even have to (16) the trees. About seventy-five feet above the ground monkeys playfully maneuver among the scattered tall trees. Around them fly the brilliantly colored birds (17) which the jungle is famous. Parrots, macaws, and toucans shrilly break the jungle (18) . Their (19) can be clearly heard. When the birds and (20) look down to the jungle floor, they are seeing jungle life as it has been for millions of years.
单选题
A. slowly B. densely C. poorly D. attractively