[单项选择]Not having been discovered, many laws of nature actually exist in nature.
A. 虽然许多自然界的规律尚未发现，但它们确实存在于自然界中。
B. 存在于大自然中的很多规律还没有被科学界发明出来。
C. 许多自然界的规律实际上存在于自然界中，尽管不能被发现。
D. 尽管很多自然界的规律没有被找出，但是这些规律实际上存在于自然界中。

[单项选择]Not having been discovered, many laws of nature actually exist in nature.
A. 虽然许多自然界的规律尚未被发现，但它们确实存在于自然界中。
B. 存在大自然中的很多法律还没有被科学界发明出来。
C. 许多自然界的规律实际上存在于自然界中，尽管不能被发现。
D. 尽管很多自然界的规律没有被找出，但是这些规律实际上存在于自然界中。

[单项选择]Not having been discovered，many laws of nature actually exist in nature．（）
A. 虽然许多自然界的规律尚未被发现，但它们确实存在于自然界中。
B. 存在大自然中的很多法律还没有被科学界发明出来。
C. 许多自然界的规律实际上存在于自然界中，尽管不能被发现。
D. 尽管很多自然界的规律没有被找出，但是这些规律实际上存在于自然界中。

[单项选择]How many laws are there discussed in the speech

[多项选择]There have been many technological developments in the 20th. century, for example, computers and electric power. Choose either of the two, describe the changes it has brought about and discuss whether all the changes are positive.
You should write no less than 250 words. Write your article on ANSWER SHEET 2.

[简答题]

Through history there have been many great explorers. Have you, for example, heard of Mar co Polo, the famous Italian traveller He was one of the first Europeans to travel to China. He arrived in China in the late 13th century. About 200 years later Christopher Columbus sailed from Spain by ship. He was looking for a new way to reach India. However, as you probably know, he did not reach India. He landed in America. Five hundred years after Columbus, in the 1930s, a famous explorer named Richard Byrd was one of the first persons to fly over both the North and the South Poles.
Today we continue to explore this world, and are starting to explore other worlds, too. In the late 1950s and the 1960s Russian and American scientists sent many unmanned spacecrafts to the moon. These spacecrafts sent back valuable information about the moon. Then on July 16,1969, the first manned spaceship to the moon left earth. On that day Apollo 11 blasted off with three American astronauts on b