阅读下面短文，从短文后所给的A、B、C、D四个选项中选出能填入相应空白处的最佳选项。

My mother is 82. Unless I have to be out of town, each week I take my mother to do her shopping and visit the doctor, since she has difficulty in walking and ______. During the week, however, she likes to go to a nearby store to buy some small things she needs.

Last week she walked up to the store, but when she went to pay for her groceries, she was ______ of three dollars. The only way to pay for the goods was to ______ the things she could do without a bottle of rubbing alcohol（医用酒精）and a bar of soap. By dropping these, she was able to bring the new total to the amount of cash she had with her.

At this store, people ______ and then went off to the side to buy their own goods. My mother was putting her groceries into shopping bags when a ______ came up to her and said, “Here are the things that you put back.” ______ her the rubbing alcohol and the soap. My mother, who is never unable to express herself, was ______. She asked for the woman’s name and address so that she could repay her. The woman told her it was her gift.

My mother was so touched by her ______ that she decided to go back to the store and give the cashier（收银员）a five-dollar bill to keep on hand in case the same happened to someone else ______.

So, whoever you are, thank you for the random act of ______ that not only helped my mother out, but made my day too.

In less than two months, a newly opened mini-market in a village in Xigaze City, Southwest China’s Tibet autonomous region, has won a large number of customers. “Trash for cash”—that is the secret behind its success. Villagers can redeem(兑换)goods with used boxes and drink bottles.

Early in the morning, Drukhyun, the first secretary of Chumik village, came to check the stock-sheet(存货单). “More and more people are coming to redeem goods and we need to timely add stocks,” Drukhyun said.

Sonam Dorje came early with a big bag of waste paper. He redeemed 16 points, which he used to get a bag of salt. “I used to throw them away directly. Now I can redeem them at the market, which is an additional income for me,” Sonam Dorje said.

Yet the move(行动)was not quite well received in the beginning, until they put their eyes on the pupils. The children used recyclables in exchange for snacks and soon the news spread. Now over 100 villagers have redeemed products with a market value of over 5,100 yuan (about $801).

Technology has also made the low-carbon lifestyle smarter and cleaner. In a community in Lhasa’s Chengguan district, the intelligent recycling bins can calculate the weight and upload the redeemed points to cards held by local residents. “When the trash bins are full, it will automatically ‘remind’ the cleaning staff to empty them,” said Pendran, director of the district’s waste sorting office. He added Chengguan district has built 220 garbage recycling stations and will install more to further perfect the whole system.

Partricia Pania never wanted to be a national public figure. All she wanted to be was a mother and a homemaker. But her life was turned upside down when a driver distracted（分心）by his mobile phone, ran a stop sign and crashed into the side of her car. The crash killed her two-year-old daughter.

Four months later, Partricia hesitantly but courageously decided to try to educate the public and to fight for laws to ban drivers from using mobile phones while a car is moving. She wanted to save other children from what happened to her daughter. In her first speech, Partricia got off to a shaky start. She was visibly trembling and her voice was soft and uncertain. But as she got into her speech, a dramatic change took place. She stopped shaking and spoke with a strong voice. For the rest of her talk, she was a forceful and powerful speaker. She wanted everyone in the audience to know what she knew without having to learn it from a personal tragedy. Many in the audience were moved to tears, and to action.

In the following presentations, Partricia became known as a highly effective speaker. Her appearance on a talk show was broadcast（播出）three times, bringing her message to over 14,000,000 people. Her campaign increased public awareness of the problem and made over 300 cities and several states consider restrictions（限制）on mobile phone use.

The manatee（海牛）is a large marine mammal（海洋哺乳动物）. Manatees are also known as sea cows because of their slow, lazy nature and their grassy meals. Although they have such a name, they are more closely related to elephants. Manatees and elephants evolved from the same ancestor（祖先）over 50 million years ago.

There are three kinds of manatees. The West Indian manatee lives along the North American east coast from Florida to Brazil. The Amazonian manatee inhabits（栖居在）the Amazon River and the African Manatee swims along the west coast and rivers of Africa. Manatees differ in size from 2.4 to 4 metres and can weigh 200 and 590 kilograms. Though they may seem cumbersome, manatees can swim quickly and beautifully. Manatees usually swim about 8 km/h, but they can swim up to 24 km/h when they feel a need for speed.

Like whales and dolphins, manatees breathe air. They go to the surface for air every three to five minutes. However, they can hold their breath underwater for up to 20 minutes. This may have to do with the size of their lungs, as they are a large part of the manatee’s body.

Manatees have been under attack by humans for a long time, threatened by fishing nets and coastal development. The IUCN’s Red List of Threatened Species lists all manatees as vulnerable（脆弱的）or endangered and facing a high risk of dying out.