问题 选择题

某植物茎杆软弱,叶的边缘和尖端呈褐色,并逐渐焦枯.上述症状说明此植物缺少的无机盐是(  )

A.含氮的无机盐

B.含磷的无机盐

C.含铁的无机盐

D.含钾的无机盐

答案

氮肥作用能促使植物细胞的分裂和生长,促使植物的茎、叶(营养生长)生长茂盛,叶色浓绿.土壤缺氮时,植株矮小,叶片黄化,老叶黄色枯焦,花芽分化延迟,花芽数减少.缺磷时,幼芽和根系生长缓慢,植株矮小,叶色暗绿,无光泽,背面紫色.缺钾时,植物易倒伏,叶片脉间缺绿,且沿叶缘逐渐出现坏死组织,渐呈焦枯状.由上可知,题干中的情况应该是缺少含钾的无机盐.

故选:D

单项选择题
阅读理解

A new study suggests that the round-the-clock(24小时不断的)availability that cell phone have brought to people’s lives may be taking a toll on family life.The study,which followed more than 1,300 adults over 2 years, found that those who consistently used a mobile phone throughout the study period were more likely to report negative “spillover’’ between work and home life—and,in turn, less satisfaction with their family life.

Spillover essentially(本质上)means that the line between work and home begins to become unclear.Work life may invade home life when a parent is taking job—related calIs at home,for instance--or family issues may start to take up work time.For example,a child may call mom at work,telling her "microwave exploded” explained Noelle Chesley,an assistant professor of sociology at the University of Wisconsin—Milwaukee and the author of the study. The problem with cell phones seems to be that they are allowing for ever more spillover between work and home.   

This may be especially true for working women,the study found. Among men,consistent use of mobile phones seemed to allow more work issues to creep (潜入)into family time.But for women,the spillover tended to go in both directions. Being “connected” meant that work cut into home time,and family issues came into work life. 

Cell phones seem to be opening more lines for stressful exchanges among family member.But there may be ways to control the spillover,according to Chesley.Employers, she said,could look at their policies on contacting employees after hours to make sure their expectations are “reasonable”.For their part,employees could decide that cell phones go off during family time, Chesley said. 

64.What does the underlined phrase “taking a toll on’’ probably mean in Paragraph 1?

A. Explaining.   B. Influencing.    C. Damaging.   D. Extending      

65.According to Chesley,what is the best solution to the problem caused by cell

phones?

A. Refuse to use cell phones.

B. Separate work hours from family time.

C. Ignore coming calls during family time.

D. Encourage women to stay at home.

66.We can learn from the passage that ___________________.

A.spillover makes the line between work and home unclear

B.cell phones seem to be convenient to families

C.cell phones affect men as much as women

D.we can do nothing to solve the problem

67. What is the main idea of the passage?

A .How to control the negative spillover caused by cell phones.

B. Cell phones cause negative “spillover’’ between work and home life.

C. Consistent use of cell phones makes people feel less satisfied with their work.

D.How work life invades home life.