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问题 选择题

下列错误操作中，通常使取得的量或测得的数据偏小的是（　　）

A．用量筒取10mL水，采用俯视方法取得的量

B．用量筒测定液体体积，采用俯视方法测得的数据

C．将砝码放在左盘，不使用游码，称量右盘物质的质量，测得的质量数据

D．将pH试纸用水润湿后测定某盐酸的酸碱度

答案

A、使用量筒量度液体体积时，视线应与量筒内液体凹液面的最低处保持水平，如果俯视，则测得的实际体积比读数偏低，所以正确．

B、用量筒测定液体体积时，视线应与量筒内液体凹液面的最低处保持水平，如果仰视视，则测得的实际体积比读数偏高，所以错误．

C、天平是一个等臂杠杆，如不使用游码，将砝码放在左盘，称量右盘物质的质量，测得的质量数据与正确操作一样，所以错误．

D、将pH试纸用水润湿后测定某盐酸的酸碱度，相当于测定稀释后的盐酸的酸碱度，测定结果偏高，所以错误．

故选A．

单项选择题

下述哪项不是心脏萎缩的肉眼特点()

A．体积小

B．呈褐色

C．心肌质地硬韧

D．心脏表面血管弯曲

E．心脏表面血管增粗
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填空题

When you stop and think about your high school or college alma mater, were your experiences more positive or negative Do your feelings of (1) in that school have anything to do with whether or not your school was single-sex or coed (2) to send their children to single-sex schools, because they feel both (3) when they study in the company of students of the same sex. They (4) .
For years, only parents who could afford to send their children to private schools, or who had (5) , chose single-sex education for their children. Single-sex schooling was (6) for most American families. Today, however, along with (7) , public schools are experimenting with the idea of (8) .
Girls may be the ones who benefit most from single-sex schooling. Studies have shown that (9) in coed classrooms because teachers sometimes pay more attention to boys. Girls’ (10) toward their studies tends to disappear as they begin to feel less successful. They start to (11) outperform them in math and science. As boys (12) , girls start to lose it. Moreover, adolescence is (13) for girls. As they experience adolescent changes, some girls become depressed, develop an addiction, or suffer from (14) .
In the early 1990s, some influential people said that being in single-sex classes could (15) . Schools across the country began creating single-sex classrooms and schools. But many critics claim that (16) may actually be detrimental to a girl’s education because they (17) of sex differences.
The renewed interest in single-sex schooling (18) among Americans. Those who give it full endorsement believe girls need an all-female environment to take risks and find their own voices. Those who (19) of single-sex schooling wonder whether students’ lack of achievement warrants returning to an educational system that divides the sexes. They believe there is no (20) .
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