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【单选题】
某学生配制了l00mL 2mol/L的NaCI溶液，然后对溶液浓度做精确测定，且测定过程中一切操作都正确。结果测得溶液的物质的量浓度低于2mol/L。那么在配制过程中，下列操作可能导致溶液浓度偏低的是 ①托盘天平称量过程中NaCI固体和砝码放反了 ②将NaCl在烧杯中稀释，转移到容积为lOOmL的容量瓶中后，没有洗涤烧杯 ③在观察液面俯视 ④最后，加水超过了刻度，马上用胶头滴管吸去多余的水，使溶液凹液面刚好与刻度线相切A.
②③④
B.
③④
C.
①②④
D.
①②③④
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【简答题】Now let us look at how we read. When we read a printed text, our eyes move across a page in short, jerky （急动的）movement. We recognize words usually when our eyes are still when they fixate. Each time t...
【简答题】Now let us look at how we read. When we read a printed text, our eyes move across a page in short, jerky movement. We recognize words usually when our eyes are still when they fixate. Each time they f...
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【单选题】When we read online, she says, we tend to become "mere decoders of information".
A.
When reading online, we choose what we like and reject what we dislike.
B.
When we read online, we passively accept the information the Internet provides.
C.
Online reading can teach us how to decode information.
D.
When we read online, we absorb information like a decoder.
【单选题】You could see the beautiful views from ________we stood. [ ]
A.
which
B.
where
C.
that
D.
when
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