在实验室中，根据达西定律测定某种土壤的渗透系数，将土样装在直径d一30 mm的圆筒中，在90 cm水

Men have traveled ever【C1】______ they first appeared on the earth.【C2】______ primitive times they did not travel for pleasure but to find new places【C3】______ their herds could feed, or to escape【C4】______ hostile neighbours, or to find more favourable【C5】______ . They traveled on foot. Their journeys were long,【C6】______ , and often dangerous. They protected【C7】______ with simple weapons, such as sticks or stone clubs, and by lightning fires at night and, above【C8】______ , by keeping together.

【C9】______ intelligent and creative, they soon discovered easier ways of traveling. They【C10】______ on the backs of their domesticated animals; they hollowed out tree trunks and, by using bits of wood as paddles, were able to travel【C11】______ water.

Later they traveled, not for necessity, 【C12】______ for the joy and excitement of seeing and experiencing new things. This is still the main reason【C13】______ we travel today. Traveling, of course, has now become a 【C14】______ organized business. There are cars and splendid roads,【C15】______ trains, huge ships and jet airliners, all of【C16】______ provide us【C17】______ comforts and security. This sounds wonderful. But there are difficulties. If you want to go【C18】______ , you need a passport and a visa, tickets, luggage, and a hundred and【C19】______ other things. If you lose any of them, your journey may be 【C20】______ .

【C1】

A．when

B．since

C．while

D．then

Men have traveled ever since they flint appeared on earth.

In primitive times they did not travel for pleasure but to【C1】______new places where their herds could feed, or to escape from【C2】______neighbors, or to find more【C3】______climates. They traveled on foot. Their【C4】______were long, tiring and often dangerous. They protected themselves with simple【C5】______such as wooden sticks or stone clubs, and by lighting fires at night and,【C6】______all, by keeping together.

Being intelligent and creative, they soon【C7】______easier ways of traveling. They【C8】______on the backs of their domestic animals; they hollowed out tree【C9】______and, by using bits of wood as paddles, were able to travel【C10】______water.

Later they traveled, not from necessity, but【C11】______the joy and excitement of seeing and experiencing new things, which is still the main【C12】______why we travel today.

Traveling, of course, has now become【C13】______organized business. There are cars and splendid roads, express train, huge ships and jet airliners, all of【C14】______provide us with comforts and security. This sounds wonderful.【C15】______there are difficulties. If you want to go【C16】______, you need a passport and visa, tickets, luggage, nd a hundred and one【C17】______things. If you lose any of them, our journey may be【C18】______.

Scientists have invented machines that can explore【C19】______space. Eventually there will be cheap day journey to the moon and honeymoons on Venus. People will be able to fly from one planet to another in nasty little arrow-shaped tubes. I say "people" because I have no【C20】______of being one of them.

【C1】

A．visit

B．find

C．buy

D．investigate

Where have men traveled in a spaceship？

A．To other planets.

B．To the moon.

C．Only on the earth.

A.suspended

B.survived

C.lingered

D.preserved

(Ever since) the world (began) nations (have difficulty) in (keeping) peace with their neighbors.

A．Ever since

B．began

C．have difficulty

D．keeping

It is/was the first time(that)I have/had ever been in a plane．

A) preserved

B) survived

C) suspended

D) lingered

Which of the following is true about Jane Eyre？

A．The first woman novelist in English literature.

B．The first woman novelist dealing with gender issues.

C．The first novel about the equality between genders in English literature.

D．The first novel in English literature.

(Ever since) the world (began), nations (have difficulty) (in keeping) peace with their neighbors.

A．Ever since

B．began

C．have difficulty

D．in keeping