Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions.It’s a sound you will probably never hear, a sickened tree sending out a distress signal. But a group of scientists has heard the cries, and they think some insects also hear the trees and are drawn to them like vulture to a dying animal. Researchers with the US Department of Agriculture’s Forest Service fastened sensors to the bark of drought-stricken trees clearly heard distress calls. According to one of the scientists, most parched trees transmit their plight in the 50-hertz to 50-kilohertz range. (The unaided human ear can detect no more than 20 kilohertz). Red oak, maple, white pine, and birch all make slightly different sounds in the form of vibrations at the surface of the wood.The scientists think that the vibrations are created when the water columns insidc tubes that run along the length of the tree break, a result of too little water following through them. These fractured columns send out distinctive vibration pattems. Because some insects communicate at ultrasonic frequencies, they may pick up the trees' vibration and attack the weakened trees. Researchers are now running tests with potted trees that have been deprived of water to see if the sound is what attracts the insects. “Water-stressed trees also smell differently from other trees, arid they experience thermal changes, so insects could be responding to something other than sound,’' One scientist said.Notes:- vulture (n): chim kền kền.- potted (adj): mọc lên trong chậu.- distress call (n): tiếng kêu báo tin nguy cấp.- oak (n): cây sồi; maple (n): cây thích; birch (n): cây cáng lò, cây bulô.
Câu 1: Which of the following is the main topic of the passage?
A. The vibrations produced by insects.
B. The sound made by trees.
C. The mission of the us Forest Service.
D. The effect of insects on trees.
Câu 2: The word “them” in line 3 refers to _________ .
A. scientists
B. trees
C. vultures
D. insects
Câu 3: The word “parched” in paragraph 1 is closest in meaning to _________ .
A. recovered
B. burned
C. damaged
D. dehydrated
Câu 4: It can be inferred from the passage that the sounds produced by the trees ________ .
A. are the same no matter what type of tree produces them
B. cannot be heard by the unaided human ear
C. fall into the 1-20 kilohertz
D. serve as a form of communication among trees
Câu 5: The word “plight” in paragraph 1 is closest in meaning to ________ .
A. condition
B. cry
C. agony
D. need
Câu 6: All the following are mentioned as possible factors in drawing insects to weakened trees EXCEPT ________ .
A. thermal changes
B. smells
C. sounds
D. changes in colors
Câu 7: Which of the following could be considered a cause of the distress signals of trees?
A. lack of water
B. attacks by insects
C. experiments by scientists
D. torn roots
Câu 8: The word “fractured” in paragraph 2 is closest in meaning to _________ .
A. broken
B. hollow
C. long
D. blocked
Câu 9: It can be inferred from the passage that research concerning the distress signals of trees _________ .
A. is no longer sponsored by the government
B. has been unproductive up to now
C. was conducted many years ago
D. is continuing
Câu 10: The phrase “pick up” in paragraph 2 could best be replaced by which of the following?
A. attack
B. lift
C. transmit
D. perceive
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