题目内容
在常见的软件生命周期中，适用于项目需求简单清楚，在项目初期就可以明确所有需求，不需要二次开发的软件生命周期模型是(48)；适用于项目事先不能完整定义产品所有需求，计划多期开发的软件生命周期模型是(49)。
查看答案
搜索结果不匹配？点我反馈
更多问题
The second kind of learning is called "operant conditioning." This occurs when an individual learns to do things that produce rewards in his environment and learns not to do things that produce punishments. For example, if a mother always attends to her baby when he cries and cuddles him until he is quiet, she may teach him that if he cries he will get attention from mother. Thus, the baby will learn to increase his crying in order to have his mother more.
Every day, we grow and have new experiences. We constantly learn by reading, watching television, interacting with other people, and so forth. This learning affects our emotions. Why is it that we learn to like some people and dislike others？ If a person is nice to us, cares about us, we learn to associate this person with positive feelings, such as joy, happiness, and friendliness. On the other hand, if a person is mean to us, does not care about us, and even deliberately does things to harm us, we learn to associate this person with negative feelings, such as unhappiness, discomfort, and anger.
What's the author's main purpose in writing the passage？
A．That street was further from his destination.B．The road condition there was very bad
W: Good idea. Where are you going？
M: I'm planning to visit China.
W: My sister and I had a vacation there last year and we had a great time.
M: Did you go to Beijing？
W: Sure. We climbed the Great Wall, traveled around the Imperial Palace and the Summer Palace.
M: Is it as mysterious as we've thought？
W: Not at all. It's just like any other international city: modem, busy and full of high buildings and large mansions.
M: Compared with Paris, which one is more beautiful？
W: Both are beautiful. Difficult to say. They belong to different styles. But I like Beijing more.
M: That's good. How about the weather them？
W: Well, when I got there, it was fall, cool and quite comfortable. But if you go now, it's winter. I'm afraid it will be a little cold them.
M: What should I do about that？
W: Oh, of course take more clothes and keep yourself warm. Just take it easy for a few days. When you are accustomed to the weather, you will feel much better.
(20)
A．He didn't make any mistakes.B．He didn't notice the signs along the street.C．He forgo
微信支付 
支付宝支付