同学们用显微镜观察细胞形态结构后，要绘制出细胞结构简图．下列错误做法是（　　）

读黄河流域图（如图），完成下列各题。

读“西亚地区图”，回答问题

依次填入下列各句横线处的成语，最恰当的一组是（     ）

①对于深陷危机的巴西足球队，外界唱衰的论调尤甚。巴西人能让这些担忧随着奥运的开幕    吗？

②岁月变迁，曾经在上海街头风光一时的老艺人们       ，经历着各自不同的命运。

③由于森林不断退化和消失，至上世纪90年代末，东北虎在中国境内基本           。

   Volunteering means that you work to help people without being paid. There are many different volunteers. They help people who really need help. There are many places where you can be volunteers. Here are just a few places for you.
   Hospital---ask if you can go and visit people who are really sick. Sometimes what they need is someone to talk to, or someone to give them hope.
   Orphanage (孤儿院) ---the children living there really need someone to play with them.
   Food Shelter---many food shelters need people to clean up the shelters and help give out food or water to those who need it.
Home for the elderly ---help the elderly people clean up their homes.
   Community (社区) Center ---a lot of community centers are very well run. However, some of them really need extra help, especially cleaning and repairs.
   As a student you can also do a lot of things to help others at school. Maybe you could start a support group.
   Here is some advice:
   Help students give up smoking, drinking or other bad habits.
   Help students who come from poor families.
   Help new students get used to their school life soon.
   Provide seniors with information on future studies.