问题 单项选择题

出现"关键路径上的活动总时差是零和负数"情况时,下列分析正确的是()

A.关键路径上的活动总时差可能为零的原因是每个相邻活动都是紧前或紧后的,需要调整以给活动留出时间余地

B.关键路径上的活动总时差可能为负的原因是由于安排调配不得当所造成的活动非合理性交错现象,有必要调整活动持续时间、逻辑关系等使得活动总时差为零

C.关键路径上的活动总时差可能为负的原因是因为用最早时间减去最晚时间,不需要调整以给活动留出余地

D.关键路径上的活动总时差可能为零的原因是活动进度没有余地,需要调整以给活动留出余地

答案

参考答案:B

解析:根据关键路径法,关键路径上的活动总时差可能为负的原因是由于安排调配不得当所造成的活动非合理性交错现象造成的,因此应选B。

阅读理解

根据材料内容选择最佳答案,并将其标号填入题前括号内。

These days, when the world seems to be hard to control, walking can make you feel peaceful. It gives you a chance to slow down, to relax and to appreciate yourself and your life in general. It helps you slow down enough to breathe deeply, to calm your thoughts, and to research the natural world filled with wonders. And yes, to love yourself more.

Try to spend one day for a long travel on foot—far from the requirements of work and family. First, choose a date and mark it as your “relaxing day”. Next, choose a place that you want to visit on foot. If you enjoy being out in nature, head to a wide and open place. Try to choose a place that’s no more than 15 minutes from your home. You want to spend your time walking, not driving.

Walk at an easy speed so you can walk longer and farther. If you normally walk two miles a day, go for four to six miles. Wear comfortable clothes. If it’s warm, wear a hat to protect your face. And don’t forget your sunglasses— not only to protect your eyes but also to give you a sense of privacy while you walk.

Before you go out, get up early so you can spend a few minutes relaxing. Relaxing is something few people spend in their spare time, but it leaves you feeling much lighter and less annoyed. Read something relaxing before you leave home, and it’ll put you in a different condition of mind. And, of course, eat a healthy breakfast and drink plenty of water. Then pick up your backpack and head out. And enjoy yourself.

小题1:From the passage, we can control our feeling by______.

A.running a long way

B.having a long walk

C.talking with best friends

D.communicating with parents小题2:Walking can help you EXCEPT _______.

A.making you calm

B.feeling more excited

C.thinking things calmly

D.breathing deeply小题3:What can you do to prepare if you plan to hike according to the passage?

A.Check the car carefully

B.Run for a long time

C.Wear comfortable clothes

D.Take enough food and water小题4:Before you go out for a walk, you should _______.

A.eat a healthy breakfast.

B.drink plenty of water.

C.get up early and relax yourself.

D.all above.小题5:From the passage, we can know________.

A.the world is very peaceful now

B.we can have a walk to relax ourselves during busy days

C.when we want to have a long walk, we should let others drive a car

D.we should have a long hike every day

单项选择题