题目内容
下面哪些因素可以影响基团的吸收频率？
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下面哪种说法是正确的？
在红外吸收光谱中，分子振动时，键或基团______不发生变化时，没有红外活性？
Directions: Listen to a conversation and choose the best answer from the four choices provided for each question.[音频]1.A) He’s going to work. B) He’s going shopping. C) He’s going home from work. D) He’s going to school from home.2.A) He studies the next day. B) He has no time to study. C) He stays up all night to study. D) He studies when he’s not exhausted.3.A) Because he doesn’t have any student loans. B) Because he doesn’t want to use his parents’ money. C) Because he doesn’t have to worry about his studies. D) Because he doesn’t want to owe too much in student loans.4.A) He has experience in managing difficult people. B) He knows the value of his work at the supermarket. C) He has experience in dealing with difficult situations. D) He knows how to make better choices between work and study.
Directions: Listen to a passage and choose the best answer from the four choices provided for each question.[音频]1.A) They preferred to stay in the clean section. B) They preferred to stay in the empty section. C) They preferred to stay in the natural section. D) They preferred to stay in the unnatural section.2.A) They gave all the fish in the fish tank some painkilling shots. B) They put painkilling medicine in the water of both sides of the fish tank. C) They put painkilling medicine in the water of the natural side of the fish tank. D) They put painkilling medicine in the water of the empty side of the fish tank.3.A) Fish that received the painful shot stayed in the natural section. B) Fish that received the painful shot moved into the empty section. C) All of the fish stayed in the natural section with plants and rocks. D) All of the fish moved into the empty section with painkilling medicine.4.A) Fish can’t feel pain when they receive shots. B) Fish can experience pain and try to reduce it. C) Fish like to swim in an unnatural environment. D) Fish like to swim in a less pleasing environment.
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