问题 问答题

一辆汽车的载重量为30t,车厢的容积为40m3,现要运输钢材和木材,已知钢材的密度为7.8×103kg/m3,木材的密度为0.5×103kg/m3,问这两种材料怎样搭配运输才能使汽车得到充分的利用?

答案

设装木材的体积为V,装钢材的体积为V,由题意可得:

 V+V=40m3 ,①

ρVV=3×104kg,

∴7.8×103kg/m3×V+0.5×103kg/m3×V=3×104kg        ②,

由①②解得:V=1.4m3,V=38.6m3

答:木材的体积取38.6m3,钢材的体积取1.4m3才能使这辆汽车的车厢得到充分利用.

阅读理解

Dear Cary,

I’m writing because I’ve understood you’ve struggled with alcoholism(酗酒).I’ve been fighting mine ever since I went through 9-11.After that,I’ve been more or less useless professionally –I’m a lawyer–and have had to resign from my job because I was discovered passed-out drunk in front of my computer. I’ve taken some medicine and it has helped somewhat. I can manage about a month without drinking,but after that I end up having a crazy stage where nothing matters except drinking.After a week or so of heavy drinking,I start having nightmares of people jumping. After that,it’s a week of not being able to get out of bed.

I was supposed to travel to a conference but didn’t make it because I got so drunk at the airport that I fell down on my face and spent the rest of the day in the emergency room. I have been hiding from my family since then.Fortunately they won’t be expecting me to come back for a week or so. Otherwise, they would notice the bump on my forehead and two black eyes.

I don’t really know what I’m asking you.Cary, I need a way out that doesn’t involve causing pain to my family.I’m taking medicine,but I still have these attacks every few months.If there’s alcohol in the house,I can’t stay away from it.It seems that this will never end. I’m afraid of what will happen if something bad happens,like a family member dying, or getting fired again.

Thanks for reading.

Yours T

小题1:The underlined sentence shows us all the following EXCEPT____________.

A.that the author is a lawyer by profession

B.that the author is a lawyer and he seldom gets drunk

C.the reason why the author had to resign

D.that the author was once discovered drunk as a fish小题2:The author writes to Cary in order to____________.

A.offer advice

B.tell a story

C.avoid nightmares

D.ask for help小题3:What is the author worried about?

A.Losing his job

B.Missing the conference

C.Bring pain to his family

D.Giving up drinking小题4:What do we learn from the passage?

A.T’s family members don’t want to see him because of his alcoholism.

B.Getting drunk once prevented T from attending a conference.

C.T will have nightmares when he stops drinking.

D.T never attempted to give up his alcoholism.小题5:We know from the passage that Cary____________.

A.likes to talk about the details of his life.

B.is an expert on treating alcoholism

C.is probably a recovered alcoholic

D.never suffered from alcoholism

单项选择题