题目

 科学家把C60和K掺杂在一起制造出的化合物具有超导性能，其晶胞如图所示。该化合物中的K原子和C60分子的个数比为（   ） A. 1:3    B. 3:1    C. 3:2    D. 2:3 答案：【答案】B 【解析】C60位于顶点和体心，个数为8×1/8＋1=2，K位于面上，个数为12×1/2=6，K原子和C60原子个数比为6：2=3：1，故选项B正确。Everyone needs friends. There is an old saying “Friends are God's way of taking care of us.” But how do you find real friendship and keep it? The American writer Sally Seamans tells young students some smart ways to find friends. Sally says finding friendship is just like planting a tree. You plant the seed and take care of it to make it grow. First, you should choose a friend. What makes a good friend? It is not because a person has money or good looks. A good friend should be kind and patient. For example, if you have a bad day, a good friend should listen to your complaints and do his or her best to help. To make a friend, you can not be too shy. You should make each other happy and share your lives. But things cannot always be happy. Even the best have fights. What should you do when you have a fight with your friend? You have to talk to him or her. When there is no one around, have an honest talk. If he or she doesn't want to talk, you could write a letter. There are three steps to being friends again: Tell him or her how you are feeling ; say what your friend has done wrong, and explain why you did this or that. Remember that friendship is the most important thing in your life. 1.Sally wants to tell students the ways to ________. A．find friends        B．plant trees         C．get happy         D．keep fit 2.What makes good friends? A good friend should ________. A．be lovely and cool                       B．be kind and patient C．have lots of money                      D．have good looks 3.Accroding to the text, you can ________ your friend after a fight. A．buy a present for B．never say a word to C．have dinner with D．write a letter to 4.What is the best title of the text? A．Teenagers and friendship B．The good friends around you C．The trouble of growing up D．The care and keeping of friends