问题 问答题 简答题

计算题:某轴应镀铬,镀层厚度为20±4µm,镀铬后与孔形成的配合为∮70H7/f7,公差值IT7=0.03;f7的es=-0.03;求(1)孔和轴的上、下偏差,(2)画出尺寸链图,(3)轴在镀铬前的尺寸是多少?

答案

参考答案:

孔的上偏差ES=0.03

孔的下偏差EI=0

轴的上偏差es=-0.03

轴的下偏差ei=-0.06

A1、A2均为增环,N为封闭环;

N=A1+A1+A2

A2=∮70-0.02×2=∮69.96

ESN=2×ESA1+ESA2

ESA2=-0.03-2×0.004=-0.038

EIN=2×EIA1+EIA2

EIA2=-0.06+2×0.004=-0.052

镀铬前轴的尺寸为∮69.96。

阅读理解

Chelsea Clinton, the 31-year-old daughter of former President Bill Clinton and Secretary of State Hillary Rodham Clinton, is stepping into her own spotlight.

According to the New York Times, NBC has hired Clinton to become a full-time special correspondent(记者) for NBC News. Her feature stories will reportedly be used in the “Making a Difference” series, which runs on “NBC Nightly News”. The sections attract people who volunteer to improve the lives of others in their communities.

When Bill Clinton won the presidency in 1992, the first lady asked the press to keep Chelsea out of the public eyes. As a young adult, Chelsea continued to avoid media attention in order to attend college and quietly enter the business world. Once her mother decided to run for the presidency in 2007, however, Chelsea made hundreds of public appearances, mostly on college campuses, to support the campaign. More recently, she has worked for New York University and promoted her father’s latest book. She is currently pursuing a doctor’s degree at Oxford.

Clinton is the second daughter of a president hired by NBC News; Jenna Bush Hager, daughter of former President George W. Bush, works as a correspondent for NBC’s “Today” show.

小题1: Chelsea Clinton continued to stay out of media attention to _____.

A.improve the lives of others

B.help her father in the election

C.study and go to the business circle

D.support her mother for the presidency小题2: What does the underlined word mean in Paragraph 2?

A.is shown

B.flows

C.is managed

D.spreads小题3: Which is the right order of the events?

a. Chelsea helped to sell Bill Clinton’s latest book.

b. Chelsea pursues her doctor’s degree.

c. Chelsea supported her mother’s career.

d. Chelsea was out of the public attention.

A.d, a, c, b

B.c, d, b, a

C.c, b, d, a

D.d, c, a, b小题4: According to the text, we can conclude that _____.

A.Chelsea Clinton is the second daughter of Bill Clinton

B.Chelsea Clinton is in favour of her parents’ careers

C.Chelsea Clinton always follows her mother’s advice

D.Jenna Bush Hager is a correspondent for “NBC Nightly News”

单项选择题