you ever the great physicist Stephen Hawking? He passed away on 14 March this year.

    National parks are large areas of public land. They give a safe home to local plants and animals. They help keep the air and water clean. They also give us the best trips. Today, there are about 7,000 national parks around the world. Forbes has listed 12 of the most beautiful ones in the world that will surprise you with their amazing landscape, geographic wonders and colourful plants and animals.

    The Grand Canyon National Park of the US is one of the natural wonders of the world. It is best known for its size and depth. It is 446 kilometres long, up to 29 kilometres wide, and 1.6 kilometres deep. The immensity of the canyon makes people feel they are very small. Every year, about 5 million people visit here. Taking a tour in the South Rim offers visitors the park's full views, while the North Rim shows beautiful wild flowers

    If you love animals, you'll like the Serengeti National Park in Tanzania. The "Big Five" live here. They are the lion. African elephant, African leopard, rhinoceros and African buffalo. The name "Big Five" came from the five animals that were the hardest to catch. Now they are what people most want to see in the wild. If you visit the park, you should never miss the migration (迁徙) of over 1.5 million wildebeest (牛羚) and 250,000 zebras every year. This is the most famous site of the park.

Since he was young, Alex has a music.

A blue whale can weigh 120 tons.

you tricks on that cat.

    If you visit the animal shelter (收容所) in Salinas, California, you'll see huge signs that have a picture of a dog and a cat on them. These signs  (put) in front of the shelter to catch people's attention. The signs make people interested in the shelter and encourage them  (visit) it—and maybe even take a cat or a dog into their homes.

    Each year, the Salinas shelter  (accept) thousands of dogs and cats. The animals are either lost ones  are left by people who can't take care of them. Of all the animals, some of  (they) are taken into new homes. Some animals are moved to other shelters to live a better life. Unluckily, some cannot be saved because they are too sick or are thought to be dangerous.

    Animal shelters provide food, medicine, and safe places for animals to sleep in. But they are not the  (good) homes. The animals have to stay in small cages. The people who work at shelters do their best to care for the animals,  the animals do not always get the attention or exercise they need.

    To prevent animals from  (become) homeless, pet doctors advise the owners to take good care  their pets. Most pet doctors also suggest people make sure their pets have  special surgery (外科手术). In this way animals won't have more babies. And it reduces (减少) the number of homeless animals.

You may become a US citizen either or after birth.

We were that place when it happened.