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【单选题】
将0．20 L 0．1 mol.L-1HAc溶液和0．20 L 0．1 mol.L-1NaAc溶液等体积混合，其pH=4．8，若将此混合溶液再与等体积水混合后，pH为 ( )A.
2．4
B.
9．6
C.
7．0
D.
4．8
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参考解析：
知识点：
皮皮学刷刷变学霸
举一反三
【简答题】研究 与 之间相互关系的科学叫做生态学。
【单选题】原来的沉积区上升为陆上剥蚀区，于是沉积作用转化为侵蚀作用，原有沉积物反而被剥蚀，直到该区再次下降为沉积区，接受新的沉积。如此，两套沉积物（成岩后的地层）之间隔着一个大陆侵蚀面，但两者的产状平行一致，这种关系称为（ ）。
A.
平行不整合接触
B.
角度不整合接触
【单选题】下面哪个是对断路器控制回路的基本要求 ( 1 )断路器操作机构中的合、跳闸线圈是按短时通电设计的,故在合、跳闸完成后应自动解除命令脉冲,切断合、跳闸回路,以防合、跳闸线圈长时间通电。 ( 2 )应具有防止多次合、跳闸的电气防跳措施。 ( 3 )断路器既可利用控制开关进行手动跳闸与合闸,又可由继电保护和自动装置自动跳闸与合闸。 ( 4 )应有反映断路器状态的位置信号和自动合、跳闸的不同的显示信号。
A.
123
B.
124
C.
234
D.
1234
【单选题】听力原文：M: How do you like the new physician who replaced Dr. Andrews? W: He may not seem as agreeable or as thorough as Dr. Andrews, but at least he doesn't keep patients waiting for hours. Q: What can ...
A.
Dr. Andrews has been promoted for his thoroughness.
B.
She disagrees with Dr. Andrews on many occasions.
C.
Dr. Andrews used to keep his patients waiting.
D.
She dislikes Dr. Andrews as much as the new physician.
【单选题】食品添加剂是指为( )和色、香、味,以及为防腐、保鲜和加工工艺的需要而加入食品中的化学合成或者天然物质。食品用香料、胶基糖果中基础剂物质、食品工业用加工助剂也包括在内。
A.
改善食品品质
B.
掩盖腐败变质
C.
掺杂掺假
D.
掩盖食品污染
【简答题】液压操动机构利用液体的（），以液压油为传递介质，将高压油送入工作缸两侧来实现断路器分合闸，是以（）驱动工作缸活塞带动触头进行分合操作。
【单选题】听力原文：M: How do you like the new physician who replaced Dr. Andrews? W: He may not seem as agreeable or as thorough as Dr. Andrews, but at least he doesn't keep patients waiting for hours. Q: What can ...
A.
She dislikes Dr. Andrews as much as the new physician.
B.
Dr. Andrews has been promoted for his thoroughness.
C.
She disagrees with Dr. Andrews on many occasions.
D.
Dr. Andrews used to keep his patients waiting.
【单选题】How many hours do Dr. Jerald Block's patients spend on the Internet every week?
A.
More than 20-30 hours a week
B.
More than 30-40 hours a week
C.
More than 40-50 hours a week
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