A

　　Though we usually associate the ancient Egyptian civilization with mummies(木乃伊) and pyramids, ancient Egyptians did come up with a number of inventions. Some of their most outstanding inventions are as follows:

Papyrus（莎草纸）

　　We owe the invention of paper to the ancient Egyptians who, as early as 3000 BC, had developed a technique of making paper from the papyrus plant that is commonly found along the banks of the Nile. These plants were placed over each other and placed under a weight for a couple of days. The quality of papyrus is clear as they are still complete almost 5,000 years after they were first written on.

Recd pen（芦苇笔）

　　With the invention of papyrus to write on, it was necessary for the ancient Egyptians to find out how they would write on it. Papyrus sheets were thick and stiff, so the tool that would be used to write with on them had to be hard too. Reed pens were invented by them to serve the purpose. These pens have been recovered from several ancient Egyptian sites, showing how widely they were used during ancient times. These pens date back to the 4th century BC.

Black ink

　　Of all the inventions by the ancient Egyptians, one of the greatest and most used was the invention of black ink, which was invented in 2980 BC. They mixed soot(煤烟) with vegetable gum and beeswax(树胶和蜂蜡). They replaced soot with other organic materials to make ink of different colors. These mixtures were quite resultful, as the Egyptian documents survive till date, in a full or partially readable condition

Water clock

　　The Egyptians invented the water clock as early as 1417 BC. It was a stone container with walls and a small hole at the bottom, through which water would fall in small drops at a constant rate.

21. What does the passage mainly talk about?

A. The ancient Egyptian history.

B. The historical role the Nile played in ancient times.

C. Some inventions of ancient Egypt.

D. Contributions ancient Egypt made to the world.

22. Which of the following statements is NOT true according to the passage?

A. Papyrus is of good quality.

B. Reed pens were widely used in ancient Egypt.

C. Ancient Egyptians could make ink in different colors

D. The water clock seems like the modern clock.

23. The underlined word "resultful" in the passage most probably means _________.

A. effective

B. harmful

C. strange

D. soft

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