问题 问答题 简答题

液压传动系统由几部分组成?

答案

参考答案:

通常一个液压系统由以下四部分组成:

①动力元件:油泵将机械能转变为液体压力能的装置;

②执行元件:油缸或油马达,将液体压力能转变为机械能的装置;

③控制元件:各种阀。控制液压系统所需的力、速度、方向和工作性能的要求;

④辅助元件:指各种管接件、油管、油箱、滤油器、储能器、压力表等,起连接输油、贮油、过滤、贮油压力能、测量等用。

阅读理解

阅读理解。

     Different countries have different customs. When you travel to another countries, please follow their

customs, just as the saying goes, " ______"

     Very often people who travel to the United States forget to tip (付小费). It is usual to tip porters who

help carry your bags, taxi drivers and waiters. Waiters expect to get a 15% tip on the cost of your meal.

Taxi drivers expect about the same amount.

     In England, make sure to stand in line even if there are only two of you. It's important to respect lines

there. It's a good idea to talk about the weather. It's a favorite subject of conversation with the British.

     In Spain, it's a good idea to have a light meal in the afternoon if someone invites you for dinner. People

have dinner very late, and restaurants do not generally open until after 9 pm.

     In Arab countries, men kiss one another on the cheek (脸颊). Your host may welcome you with a kiss

on both cheeks. It is polite for you to do the same.

     In Japan, people usually give personal or business cards to each other when they meet for the first time.

When a person gives you a card, don't put it into your pocket right away. The person expects you to read it.

     Don't forget to be careful of your body language to express something In conversation. A kind of body

language that is acceptable in one culture may be impolite in another.

1. When you travel to the USA, you don't need to tip ______.

A. porters

B. waiters

C. 70 minutes

D. 90 minutes

2. The missing sentence in the first paragragh should be "______".

A. Love me, love my dog

B. He who laughs last laughs best

C. When in Rome, do as the Romans do

D. Where there is a will, there is a way

3. The underline word "porters" in the passage means ______.

A. 搬运工

B. 清洁工

C. 接线员

D. 售票员

4. Which of the following is TRUE according to the passage?

A. In Spain, People usually have dinner very early

B. In England, It's a not polite to talk about the weather

C. In Arab countries, men kiss one another on the cheek

D. In Japan you should not read the business card as soon as you get it.

5. What's the best title of the passage?

A. How to Tip

B. Body Language

C. When to Have Dinner

D. Advice to International Travellers

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