Câu hỏi:

Mark the letter A, B, C, D on your answer sheet to indicate the underlined part that needs correction in each of the following questions:

If you think carefully before making your decision, you will avoid to get into trouble later.

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 50kilohertz 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 inside 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 patterns. 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, and they experience thermal changes, so insects could be responding to something other than sound”, one scientist said.

Question: Which of the following is the main topic of the passage?

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 50kilohertz 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 inside 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 patterns. 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, and they experience thermal changes, so insects could be responding to something other than sound”, one scientist said.

Question: It can be inferred from the passage that research concerning the distress signals of trees______.

Mark the letter A, B, C or D on your answer sheet to indicate the most suitable respone to complete each of the following exchanges.

Mary: “Our team has just won that English Competition.” - Anne: “_____”

Mark the letter A, B, C, D on your answer sheet to indicate the underlined part that needs correction in each of the following questions:

A lot of  rice  were  exported  to France last year.

Mark the letter A, B, C, D on your answer sheet to indicate the word whose underlined part differs from that of the other three in pronunciation in each of the following questions:

Mark the letter A, B, C, D on your answer sheet to indicate the word whose underlined part differs from that of the other three in pronunciation in each of the following questions: