【推荐1】Brain fitness has basic rules: variety and curiosity.     1     If you can do the crossword puzzle in your sleep, for example, it’s time for you to move on to a new challenge in order to get the best workout for your brain. Curiosity about the world around you, how it works and how you can understand it will keep your brain working fast. Use the ideas below to make your brain smarter.

1. Play Games

Brain fitness programs and games are wonderful ways to challenge your brain.     2     These games depend on logic (逻辑), word skills, math and more. These games are also fun. You'll get benefit more by doing these games a little bit every day.

2. Tell Stories

    3     Practice telling your stories, both new and old, so that they are interesting and fun.

3. Exercise Your Body to Exercise Your Brain

    4     By moving your body, your brain has to learn new muscle (肌肉) skills, judge distance and practice balance. Choose a variety of exercises to challenge your brain.

4.     5    

We love our routines (常规). But the more something is “second nature”, the less our brains have to work to do it. Change ways to the grocery store, use your opposite hand to open doors and eat dessert first. All these will force your brain to wake up from habits and pay attention again.

A．Make Simple Changes.

B．Have hobbies and pastimes.

C．Physical exercise is great brain exercise too.

D．To really help your brain stay young, challenge it.

E．When anything you do becomes second nature, you need to make a change.

F．Crosswords and electronic games can both improve your brain’s speed and memory.

G．Stories are a way that we strengthen memories, tell about events and share moments.

【推荐1】A group of volunteers joined forces to form a human chain to free four dolphins which had been stranded (搁浅) in a canal for four days. The four dolphins were seen in the water near the Fossil Park, Florida, US, on Sunday. Experts from the Florida Fish and Wildlife Conservation Commission (FWC) had monitored the dolphins’ activities in the past few days and hoped that they would swim out with the tide (潮水).

But when the dolphins struggled to leave the canal, brave volunteers joined members of the National Oceanic and Atmospheric Administration and the Clearwater Marine Aquarium to form a rescue team to free them. Dozens of people gathered to take videos and pictures of the kind act. A team of 14 volunteers held hands to act as a block to guide the dolphins out of the narrow channel. They shouted and patted the water with their hands to direct the dolphins to the vast waters of Riviera Bay. Dolphins find their way in the water through echolocation (回声定位). That means, by making high-frequency sounds, they can recognize the echoes of sound waves to find their way around.

Andy Garrett, a biologist of the FWC said, “We were able to keep that chain together. The dolphins were interested. They actually came over right away.” He added that when the team reached a bridge, the dolphins appeared a bit nervous and started doing some spins. “They made one real hard pass at our team and then went under the bridge and took off,” Garrett said. The operation lasted about 45 minutes and the rescue team did not use nets or any items that could stress the dolphins.

1. What can we know about the dolphins from paragraph 1?

A．They swam in groups to protect themselves.

B．They lived in the water near Fossil Park.

C．They were observed in secret by volunteers.

D．They were forced to stay in a canal for four days.

2. Why did volunteers shout and pat the water?

A．To make sounds to attract some people.

B．To guide the dolphins to larger waters.

C．To celebrate the success of saving dolphins.

D．To test the different reactions of four dolphins.

3. What words could best describe the rescuers?

A．Brave and caring.	B．Absorbed and humorous.
C．Smart and generous.	D．Independent and energetic.

4. What’s the main idea of the text?

A．Dolphins swam to the canal to hunt for food.

B．Rescuers formed a human chain to save dolphins.

C．Volunteers trained four dolphins to find their way home.

D．Experts studied the ways of dolphins finding directions.

【推荐2】This morning we're going to head off down into the wetland, into a very specific kind of wetland called the Prairie fen.

You can find Nate Fuller counting butterflies. The Sarett Nature Center needs an accurate count of Mitchell's satyr butterflies to help preserve one of their last known habitats. They're very particular about the kind of habitat where they can live, which is part of what makes them so rare and amazing indicators for our water quality. Today, Sarett expert Ashley Cole-Wick with Michigan's Natural Features Inventory helps Fuller count. She says "When I first started working on the butterfly in 2013, we had 18 populations and this year in 2019, we have 10."

The Mitchell Seder went on the endangered species list in 1991. Initially it was thought that loss of wetlands contributed to their decline. Fuller says "It's not just habitat availability. Its groundwater and the amount in the quality of groundwater coming into these wetlands seem to be a challenge for the butterfly. Nothing has all been sorted out exactly. ” While the decline is likely a combination of factors. the fact that water quality might contribute is alarming because the wetlands are the headwaters for the Midwest's rivers and streams.

A captive breeding （人工繁殖）program was started four years ago at the Toledo Zoo to help get to the bottom of the mystery. Today Director Ryan Walsh who heads the program says it's been, the only successful captive program. The caterpillars （毛毛虫）spend the winter in a special weather control room that help determine the Mitchell satyrs don't do well below 4. 4 degrees Celsius, a temperature that prevents the Fen wetlands from the hard freezes which kill the insects. With that knowledge, the program produced 1300 new eggs this summer, a development that may go a long way toward restoring the population. And if all goes well, may one day the Mitchell satyr butterfly earn a ticket off Endangered Species List.

1. What are the indicators for the water quality?

A．The habitats.	B．The butterflies.
C．The wetlands.	D．The experts.

2. What is the main idea of the third paragraph?

A．The importance of water quality.

B．Actions taken to protect the butterflies.

C．The reasons why the butterflies decline.

D．The natural conditions for the butterflies.

3. What does the underlined word "restoring" in Paragraph 4 most probably mean?

A．Preserving.	B．Increasing.
C．Recovering.	D．Controlling.

4. What can we learn about the butterfly?

A．It can easily be found.	B．It is not endangered now.
C．It will die above 4. 4 degree Celsius.	D．It can be bred by humans.