A. Giraffes usually sleep standing up and they sleep for half an hour every day. They get most of their water from the plants that they eat and only need to drink water every few days.
B. Venus (金星) is the second closest planet to the Sun. It's also the second brightest in the night sky after the Moon.
C. Antarctica (南极洲) is the only continent on Earth with no rivers. The coldest temperature there is-89.2℃. It is the world's coldest land.
D. Big Ben is a famous clock tower in London. Standing over 97 metres tall, the tower is the traditional landmark of London. It has helped keep London on time for 160 years!
E. The Siberian tiger mainly comes from China and Russia. It is one of the "World's Top Ten Endangered Animals" because of its small number.
F. The Yellow River is the Mother River of China. It's the second longest river in China after the Yangtze River. It starts from the Bayan Har Mountains and runs into the Bohai Sea.
