题目内容
工作面有2个或2个以上自由面时，煤层中爆破最小抵抗线不得小于()m。
A0.3
B0.5
C0.8
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矿井采掘工作面进风流中，氧气浓度不低于()%。
A 18
B 20
C 12
D 0.5
下山掘进的安全问题主要是()。
A 顶板
B 防瓦斯
C 防跑车
没有爆炸材料制造厂的矿区总库，所有库房贮存的各种雷管总量不得超过该库()个月的计划需用量。
A 1
B 2
C 3
D 6
根据以下内容，回答题。
Passage One
There has been， in history， a man who was swallowed by a whale and lived to tell the tale. The man"s name is James Bartley. The records to prove his unusual experience are in the British Admiralty.
Bartley was making his first trip on the whaling ship Star of the East. Suddenly the lookout sighted a huge sperm whale. The whalers knew it was a huge whale by the size of the spray it blew into the air. They lowered their small boats. James Bartley was in the first longboat. The men rowed until they were close to the whale. A harpoon was thrown and it found its mark. It sank into the whale"s flesh. The maddened beast crashed into the boat， snapping its tail at the men and the wreckage of their boats. When the survivors were picked up， James Bartley was missing.
Shortly before sunset， the whale was finally captured. The sailors tied the whale"s dead body to the side of the ship. Because of the hot weather it was important that they cut up the whale right away. Otherwise， the meat would begin to rot and oil would begin to spoil. When they got to the stomach， they felt something moving about wildly. They thought it would be a big fish still alive inside. But when they opened the stomach they found James Bartley. After this trip， Bartley settled in England， and never returned to sea.
This passage is mainly about__________. 查看材料
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