In 1803，the United States acquired a huge new piece of land called the Louisiana Territory.Meriwether Lewis and William Clark were given the job of leading an expedition to collect data about this uncharted territory.President Thomas Jefferson gave Lewis and Clark three tasks for the journey：Find an all-water route to the Pacific Ocean，make friends with the Native Americans along the way，and gather detailed information about the plants，animals，landforms（地形），and climate of the area.
   In order to discover if there was an all-water route to the Pacific Ocean，Lewis and Clark attempted to travel up the Mississippi River by boat.In this way，they hoped that they would eventually reach the Pacific.Ultimately，the explorers discovered the Rocky Mountains and the Continental Divide，but not the Pacific Ocean.The hope for an all-water route from the East to the Pacific would have to be abandoned.
   Lewis and Clark's second task was to make friends with Native Americans in the area.They packed hundreds of pounds of gifts for the indigenous people，including beads，sewing needles，cloth，yarn，and knives.Their intention was to use these items as offerings of peace and good faith.However，many tribes were hostile.They felt threatened by the Americans' presence and refused to communicate with them.Other tribes were more welcoming and aided the explorers in finding food and navigating the new region.
   The explorers' final task was extensive and ongoing.Lewis and Clark had to take detailed notes about the landforms and climate of the different areas through which they travelled.President Jefferson also wanted samples of notable plant and animal life.They prepared animal fur and plant samples to send back to the president throughout the trip.They also kept individual journals with detailed descriptions and drawings of the environment and terrain（地勢）.
   Up the Mississippi and Missouri rivers，across the Great Plains，over the Rockies，down the Columbia River，and to the Pacific Ocean，Lewis and Clark travelled.After 3 years，Jefferson received a letter from Lewis stating， "It is with great pleasure that I announced to you the safe arrival of myself and my partner.In obedience to your orders，we have penetrated（穿過）the continent of North America to the Pacific Ocean. "

（1）Which of the following is Not among the tasks that President Thomas Jefferson gave Lewis and Clark？

C

C

A．Find a direct waterway from the U.S.to the Pacific Ocean.
B．Collect geographic and ecological information about the unknown area.
C．Locate the Rocky Mountains and the Continental Divide.
D．Build relationships with the Native Americans on the way.
（2）What does the underlined word "hostile" in Paragraph 3 probably mean？

B

B

A．Determined not to change their attitudes.
B．Very unfriendly or aggressive.
C．Not wanting to talk to other people.
D．Belonging to a very simple society.
（3）What can we learn about the final task？

C

C

A．The task was less challenging than the former two tasks.
B．The task required a wide range of knowledge and skills.
C．The task focused on collecting data about landforms and climate.
D．Lewis and Clark didn't send back samples until they finished their journey.
（4）What can we infer from the text？

D

D

A．Lewis and Clark had to turn back before completing their tasks.
B．Lewis and Clark successfully found an all-water route to the Pacific Ocean.
C．Lewis and Clark finished the expedition without the help of Native Americans.
D．The expedition covered the area from the Mississippi River to the Pacific Ocean.