Here are the correct answers for the blanks in the passage:

1. **B. Important**
Community service is very **important** in social life.

2. **B. Has**
So it is necessary for us to take part (in volunteer activities) to help poor people and elderly people. Our social life **has** both the rich and the poor people.

3. **A. In**
So it is necessary for us to take part **in** volunteer activities to help poor people and elderly people.

4. **D. Raise**
Besides, we can join volunteer activities to **raise** funds for the poor and the homeless in our country.

5. **C. Talking**
Finally we can spend time **talking** with older people, sharing with poor children.

6. **A. by**
Through these activities, we can develop our leadership skill **by** organizing fundraising, providing food as well.

So the completed passage is as follows:

Community service is very **important** in social life. As you know, our social life **has** both the rich and the poor people. So it is necessary for us to take part **in** volunteer activities to help poor people and elderly people. We can help them in various ways. Firstly, it is easy for us to collect old clothes which we don’t need. Besides, we can join volunteer activities to **raise** funds for the poor and the homeless in our country. Finally, we can spend time **talking** with older people, sharing with poor children. Through these activities, we can develop our leadership skill **by** organizing fundraising, providing food as well.