Read the following paragraphs loudly.请大声朗读下面的段落 3 He then filled a cup with some of the petrol, some of the castor oil and some of the vinegar. As the students watched him quietly, he mixed the three together. After that, he held up one of his fingers and showed it to the class. He then dipped it into the cup. After a few seconds he took his finger out. “Now watch,” he said. “Remember, you must do everything as I do.” 4 He put a finger in his mouth, tasted it and smiled, looking rather pleased. Then he handed the cup around the class of students. Each student dipped a finger into the mixture and sucked it. Instead of smiling, each of them made a face. The mixture tasted terrible.