琥珀色材料，密度1.08g/cm3，折射率1.54，在饱和盐水溶液中不下沉，用乙醚擦
题型：单项选择题
问题：
琥珀色材料，密度1.08g/cm3，折射率1.54，在饱和盐水溶液中不下沉，用乙醚擦拭不变粘，应该是（）.
A.琥珀
B.塑料
C.硬树脂
题型：单项选择题
根据短文内容及首字母提示,补全空格内单词，使短文完整、通顺。（请在答题卡上写出完整单词）
True friends are hard to find. Often you thought you could believe in someone, b 1 later he or she may let you down (让你失望).
A true friend is someone who will always be there for you. Through good times or b 2 times, they will stand by your side. They will not l 3 you alone when things get difficult. They will accept you without trying to change you. A friend will b 4 new and exciting things into your life and make it richer.
True friends will keep your worst secrets as you will keep t 5 . They will be honest and you can always believe in them. If you talk to someone who you believe in, you don’t have to w 6 about what you may say. We can enjoy this freedom only with friends.
Friendship is a two-way street. To find a true friend and keep the friendship b 7 you, you must do the same thing as well. Be there for your friends when they are in n 8 and share the good times with them. Offer them the same things they give to you. Friendship will break quickly if only one person is giving and p 9 effort into it.
You will find that there is nothing more valuable t 10 having a true friend by your side to share life with, just as someone says, “There is nothing on this earth more to be prized (珍惜) than true friendship”.