问题
多项选择题
某工程双代号网络计划如下图所示，图中已标出每项工作的最早开始时间和最迟开始时间，该计划表明（）。
A.关键线路有2条
B．工作1—3与工作3—6的总时差相等
C．工作4—7与工作5—7的自由时差相等
D．工作2—6的总时差与自由时差相等
E．工作3—6的总时差与自由时差不等
答案
参考答案：A, B, D
搜题请搜索小程序“爱下问搜题”
某工程双代号网络计划如下图所示，图中已标出每项工作的最早开始时间和最迟开始时间，该计划表明（）。
A.关键线路有2条
B．工作1—3与工作3—6的总时差相等
C．工作4—7与工作5—7的自由时差相等
D．工作2—6的总时差与自由时差相等
E．工作3—6的总时差与自由时差不等
参考答案：A, B, D
| 阅读理解。 |
| It's easier to go down the hill than to climb up the hill, so it is easier to fall into bad habits (习惯) than into good ones. Bad habits do not come suddenly. They come little by little without one being aware of (意识到) their danger. School boys first pick up little bad habits in the school and on the street. When they can't write their lessons, they copy from their schoolmates. If they see bigger boys smoking, they also want to learn to smoke. If they see their friends gambling (赌博), they want to gamble. When they get bigger, the habits become stronger and stronger, so that they can no longer get rid of (摆脱, 除掉) them. From copying, they learn to steal, from gambling, they learn to cheat (欺骗). At last they become distrusted (不信任) by everybody. How necessary it is that we get rid of the bad habits in the beginning. |
| 1. It is easier to fall into ______ than into ______. |
[ ] |
| A. good habits, bad ones B. bad habits, good ones C. bad habits, good one D. good habits, bad one |
| 2. Bad habits come ______. |
[ ] |
| A. suddenly B. little by little C. faster and faster D. slower and slower |
| 3. Where do school boys pick up little bad habits first? |
[ ] |
| A. In the school. B. On the street. C. In the school and on the street. D. In a hospital. |
| 4. When school boys get bigger, their bad habits become |
[ ] |
| A. stronger and stronger B. weaker and weaker C. better and better D. less and less |
| 5. It is important for us to ______. |
[ ] |
| A. copy others B. learn steal and cheat C. get rid of the bad habits in the beginning D. laugh at others |