题目内容：

阅读下面材料，在空白处填入适当的内容（1个单词）或括号内单词的正确形式。

In the distant past, friend relied on each other for their survival. They hunted together and defended each other against1._________(danger) animals and enemies. In those days, if you didn’t have a friend, you would either starve, be eaten 2._________ killed. Nowadays, friendship isn’t 3._________(exact) a matter of life and death. However, friendship is still of great importance and not having a friend is something to be4._________(concern) about. Most people look upon friends as someone they can depend on when they are going 5._________ times of trouble. In such times, friends provide them with emotional support and sometimes financial help. It is in these troubled times6._________ they find out who their true friends are. As an old saying 7.__________(go), in times of prosperity, friends will be plenty; in times of8.__________(suffer), not one in twenty. And there is another saying9._________ says you can hardly make a friend in a year, but you can easily upset one in an hour. So do your best to get along with and be grateful to all those 10.__________ are willing to side with you even when you are in the wrong as they are true friends and they are not easily come by.