There are a number of ways to help improve your memory, so you shouldn't____sad.

    My first way is that if you want to remember something, you have to review it____.You may want to go over the material two days after you have____it, then a week later, then two weeks later, and then a month later. After a month you will find that you can remember the material.

    My second____is to use a colored pen to highlight(用颜色标出) the important parts on your book. This will help you in two ways. First, it will help you focus on the____parts when you learn the knowledge. It is always____than remembering everything.____this will make reviewing better. When you open your book, the color parts will show you the most important things immediately.

    Another good time for remembering information is in the morning because you have just ____the whole night and your brain is fresh and clear. So it's easy to remember the important information in the morning.

①若a＜b，则a²＜b²；

②若a≥b＞﹣1，则 $\frac{a}{1+a}$ ≥ $\frac{b}{1+b}$ ；

③若正整数m和n满足m＜n，则 $\sqrt{m\left(n-m\right)}$ ≤ $\frac{n}{2}$ ；

④若x＞0，且x≠1，则lnx+ $\frac{1}{1nx}$ ≥2．

其中所有真命题的序号是____

下列植物器官中，属于生殖器官的是（  ）

你认为陈涉建立政权前后成功和失败的原因各是什么？我们能从中得到什么启示？

①井冈山精神 ②长征精神

③延安精神 ④“两弹一星”精神