中,已知
,则数列
的前
项和为
.

A.5月5日 B.2月5日
C.8月5日 D.11月5日
B .
C .
=1+x写成用含x的代数式表示y的形式,以下各式正确是( )
+1
B . y=
+
C . y=
+1
D . y=
+
鸡会辨认食槽
B .
老鼠拉杆取食
C .
蚯蚓走迷宫
D .
老母鸡抚育小猫
①加快产业结构升级优化②重视发挥高端人才的作用
③大力发展金融等服务业④继续大力发展传统制造业
如图,已知BC∥DE,则下列说法中不正确的是 ( )
形的位似中心
C . AE︰AD是位似比
D . 点B与点E、点C与点D是对应位似点
2MgO+C中,氧化剂是 ( )
下图为有关种群增长的模型,下列说法不正确的是( )
Some people shy away from traveling alone while a few welcome it. So, what is it that makes traveling alone an attractive choice?
First of all, the travel plan and all the decisions you make are yours alone. You don't need to worry about any other person or group. In other words, there are no arguments. Actually, you can be completely selfish.
Traveling alone is also a great confidence builder. Yes, at times it can feel a bit lonely, but that is just one of many problems you will have to solve yourself, along with making your own preparations and setting your own goals.
Besides, have you noticed that when you're on your own, people are more willing to start a conversation with you? Interestingly, people tend to keep a distance from couples and groups. However, the lone (独自的) traveler looks ready to connect with their fellow human beings and more likely to get into pleasant conversation about their trips.
Here are two more exciting reasons why you should consider traveling alone. You will find you learn the language faster when you don't have someone else talking to you in your own language all the time. You are forced to communicate in the foreign language when you travel alone in a country that doesn't speak your native language. In addition, when you're on your own, you're free to meet someone who might turn out to be very important in your life.
Of course, there may be things stopping you: You fear the unknown, or you have friends who may be upset by your decision to take off by yourself. You will have to make them believe the value of traveling done and allay any fears they might have, but with the technology at our fingertips, you can include them in the adventure.
| 选项 | 条件 | 离子组 | 离子共存判断及反应的离子方程式 |
| A | 滴加氨水 | Na+、Al3+、Cl-、NO3- | 不能大量共存,Al3++3OH-=Al(OH)3↓ |
| B | 由水电离出的H+浓度为1×10-12mol•L-1 | NH4+、Na+、NO3-、Cl- | 一定能大量共存 NH4++H2O⇌NH3•H2O+H+ |
| C | pH=1的溶液 | Fe2+、Al3+、SO42-、MnO4- | 不能大量共存,5Fe2++MnO4-+8H+=Mn2++5Fe3++4H2O |
| D | 通入少量SO2气体 | K+、Na+、ClO-、SO42- | 不能大量共存,2ClO-+SO2+H2O=2HClO+SO32- |


sky blue?