问题
单项选择题
某药按零级动力学消除，其消除半衰期等于
A．0.693/k
B．k/0.5C0
C．0.5C0/k
D．k/0.5
E．0.5/k
答案
参考答案：C
解析： 零级消除动力学是药物在体内以恒定的速率消除，即不论血浆药物浓度高低，单位时间内消除的药物量不变。药物消除半衰期是血浆药物浓度下降一半所需要的时间。
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某药按零级动力学消除，其消除半衰期等于
A．0.693/k
B．k/0.5C0
C．0.5C0/k
D．k/0.5
E．0.5/k
参考答案：C
解析： 零级消除动力学是药物在体内以恒定的速率消除，即不论血浆药物浓度高低，单位时间内消除的药物量不变。药物消除半衰期是血浆药物浓度下降一半所需要的时间。
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| Many language learners think their pronunciation is good enough because their teacher doesn't correct them too often or because other students can _1_ them. Pronunciation is the area which is _2_ the least attention to in language learning. Most teachers _3_ just let their students speak and stop them 4 they say something completely wrong. Working on each student's pronunciation in class is just 5 . Also, the students who are 6 at pronunciation may be afraid that it will embarrass their classmates if they help 7 their mistakes. If you believe your pronunciation is good enough to 8 because it is good enough for your teacher and other students, you may be 9 when you actually go to a foreign country. One of my friends was the best student in his 10 class in Poland. When he went to America, he found Americans didn't understand 11 of what he said. Your pronunciation may still be quite 12 that of a native speaker. If this is the 13 , other people will find it 14 to understand what you're saying and will not be comfortable with you. 15 , don't think you can communicate in a foreign language 16 you've tested your skills on real native speakers. 17 for native or nearnative pronunciation so that people you talk to can communicate with you 18 . In order to achieve this goal, there's 19 that you will need to start thinking about pronunciation and 20 time on it. | ||||
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