Cloze test. Read the passage and choose the best answer for blank 4.

A Kind Act

Last Sunday, it was raining heavily. I was waiting for the bus when I saw an old lady __1__ a heavy bag. She looked very tired. I walked up to her and __2__ to carry the bag for her. She smiled and said thanks. On the bus, she told me she was going to see her grandson. I felt __3__ because I could help someone. Sometimes a small act of __4__ can make a big difference.

（第 4 空）