题目内容：

阅读下面短文，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。

Have you ever been too shy to express thanks towards someone? Well, a new study says you should not worry about that so much.

Recently, researchers have published a study on how people gave and1.(receive) letters of thanks.2.they found was that expressing and receiving appreciation increased3.(happy) for both sides, but people's self-consciousness (自我意识) often made4.less possible for them to express their appreciation.

In the experiments, the researchers asked5.(hundred) of participants to write an email to someone close to them6.(express) their appreciation and giving7.specific example of how that person made their lives better.

The writers often underestimated (低估) the positive effect that the emails would have8.the receivers. They thought that the receivers would feel9.(awkward) and uncomfortable over the letters than they actually were. Contrary to the writers' belief, the receivers were thankful, warm and understanding.

So next time you feel hesitant about expressing your appreciation for others, remember that it will most10.(probable) go a lot better than you think.