请在资料一栏找到音频1-4-4,收听并完成下面练习 SECTION 4 Questions 31-40 Questions 31-33 Choose the correct letter, A, B or C. Monosodium Glutamate (MSG) 31 The speaker says the main topic of the lecture is A the history of monosodium glutamate. B the way monosodium glutamate works. C where monosodium glutamate is used. 32 In 1908, scientists in Japan A made monosodium glutamate. B began using kombu. C identified glutamate. 33 What change occurred in the manufacture of glutamate in 1956? A It began to be manufactured on a large scale. B The Japanese began extracting it from natural sources. C It became much more expensive to produce. Questions 34-40 Complete the notes below. Write NO MORE THAN TWO WORDS for each answer. Monosodium Glutamate(MSG) • MSG contains -glutamate(78.2%) -sodium(12.2%) -34 (9.6%) • Glutamate is found in foods that contain protein such as 35 and 36 . • MSG is used in foods in many different parts of the world. • In 1908 Kikunae Ikeda discovered a 37 . • Our ability to detect glutamate makes sense because it is so 38 naturally. • John Prescott suggests that: -sweetness tells us that a food contains carbohydrates. -39 tells us that a food contains toxins. -sourness tells us that a food is spoiled. -saltiness tells us that a food contains 40 .