【正文】 hours B. old items are not allowed to bring back on the way home C. you are not allowed to carry things as freely as you want D. you can also board the plane without your passport D It was like a door that had been left open invitingly. Bob stepped through, and immediately regretted it. He was standing in a dim lowceilinged cave, the walls carved out of solid ice. There were five children there, huddling（擁抱） together in corner, their eyes fixed hopefully on his. They were dressed exactly as he was, in pale sheepskin jackets and trousers, with matching boots, and caps pulled down over their ears. All of them were in their mid teens, and their faces, pinched（皺縮） as much by fear as with cold, seemed strangely familiar, as though he had known them all his life. A girl with intense dark eyes nodded towards the end of the room. When he failed to respond, she nodded again, more urgently than before, her lips forming words soundlessly. He saw then what he should have seen earlier, a second door set low in the end wall. It was much smaller and far less noticeable than the first, yet he felt drawn to it just the same. Or was he merely being encouraged by his silent panions? Another of them, a timid boy, gave him a smile of encouragement, which was instantly reflected in all the other faces. He found it difficult to resist, as if this, after all, was why he was here to help them out in their mysterious adventure. And under the pressure of their bined request, he bent down and crawled through the low opening. This time he emerged onto a windswept ledge（巖壁） . Above him, dark grey clouds racked across an even grey sky Below—far below—lay a deserted valley heaped with slabs（厚片） of ice. 68. When Bob entered the cave, he knew that he _____. A. was wele B. was unwele C. had frightened the children inside D. couldn’t leave the cave 69. The children huddled together because they were _____. A. of one family B. trying to keep warm C. afraid of Bob D. determined to stay together 70. The girl nodded towards the end of the cave because she _____. A. didn’t dare to speak to Bob B. couldn’t speak Bob’s language C. wanted Bob to know their situation D. was too hungry to speak 71. Bob went through the second door because _____. A. he found it too cold in the cave B. the timid boy forced him to do so C. it led to a mysterious unknown place D. the children wanted him to do so E All through history， explorers have led the way for people to move into new places. Today’s explorers are responsible for leading the way into space. The first person in space was Yuri Gagarin from the Union of Soviet Socialist Republics (USSR). Mr. Gagarin was sent into the space on April 12, 1961 aboard Vostok 1. The Vostok 1 spaceship reached a point 325 kilometers (203miles) high before it began to fall back to earth. Mr. Gagarin’s journey only lasted 108 minutes, but that first trip into space marked the opening of the Space Age. The first woman in space was Valentina Tershkova who was also from the USSR. Ms. Tershkova circled the earth for two days and 22 hours aboard Vostok 6 in 1963. During this journey, Vostok 6 pletely circled the earth 48 times! Some of the people who have traveled in space leave the earth entirely. 12 people have actually walked on the moon. Neil Armstrong from the United States was the first man to set foot on the moon. When the Apollo 11 space team landed on the moon, Mr. Armstrong was the first person to step out of the ship, the Eagle, onto the moon on July 21, 1969. The last people to visit the moon were members of the Apollo 17 space team in 1972. These men spent almost three days on the moon picking up rocks and collecting soil from the surface of the moon. They brought these samples back to earth for scientists around the world to study. For the time being, only about 300 people from all around the world have gone into space, but this number will surely increase as scientists continue to explore space. 72. Where was the first man in space from？ A. England B. Germany C. the USA D. the USSR 73. How long was Yuri Gagarin’s first space flight？ A. less than two hours B. more than a week C. about one day D. a few months 74. Whe