问题
多项选择题
下列属于胃蛋白酶特点的有( )。
A．初始无活性
B．最适pH=2.0，pH＞6.0则失活
C．安静时，以少量、恒定的速率分泌
D．刺激时，大量、迅速地分泌
E．已形成的蛋白酶可反作用于蛋白酶原
答案
参考答案：A,B,C,D,E
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下列属于胃蛋白酶特点的有( )。
A．初始无活性
B．最适pH=2.0，pH＞6.0则失活
C．安静时，以少量、恒定的速率分泌
D．刺激时，大量、迅速地分泌
E．已形成的蛋白酶可反作用于蛋白酶原
参考答案：A,B,C,D,E
The teacher thought that hobbies were very important for every child. She 20 all her pupils to have one, and sometimes, arranged for their parents to come and 21 the work they had done as a result. One Friday morning the teacher told the class that 22 of them who had a hobby could 23 a holiday that afternoon to get things they had 24 as parts of their hobbies ready for their parents to see the following afternoon. So on Friday afternoon, 25 those of the pupils who had nothing to show did their usual lessons, the 26 ones who had made something were allowed to go home, on 27 that they returned before five o’clock to bring what they were going to 28 . When the afternoon lessons began, the teacher was 29 to see that Tommy was not there. He was the laziest boy in the class, and the teacher found it difficult to believe that he had a hobby. However, at a quarter to five, Tommy arrived with a 30 collection of butterflies in glass cases. 31 his teacher had admired them and helped him to arrange them on a table in the 32 , she was surprised to see Tommy pick them up again and begin to 33 . “What are you doing, Tommy?” she asked. “Those things must 34 here until tomorrow afternoon. That’s 35 the parents are coming to see them.” “I know they are coming then,” answered Tommy, “and I will 36 them back tomorrow, but my big brother doesn’t want them to be out of our house at night in case they are 37 .” “But what has it got to do 38 your big brother?” asked the teacher. “Aren’t the butterflies yours?” “No,” answered Tommy. “They belong to him.” “But Tommy, you are 39 to show your own hobby here, not somebody else’s!” said the teacher. “I know that,” answered Tommy. “My hobby is watching my brother collecting butterflies.”
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