题目

在管子内部抗压实验时，利用注水加压直至水管破裂的方法，测试水管的最大承压能力。这种实验方法属于（   ） A . 性能实验法 B . 预测实验法 C . 强化实验法 D . 虚拟实验法 答案：CLying in the sun on a rock, the cougar(美洲豹)saw Jeb and his son, Tom before they saw it. Jeb put his bag down quickly and pulled his jacket open with both hands, making himself look big to the cougar, It worked.  The cougar hesitated, ready to attack Jeb, but ready to forget the whole thing, too.Jeb let go of his kacked, grasped Tom and held him across his body, making a cross.  Now the cougar’s enemy looked even bigger, and it rose up, ready to move away, but unfortunately Tom got scared and struggled free of Jeb.“Tom, no” shouted his father.But Tom broke and ran and that’s the last thing you do with a cougar.  The second Tom broke free; Jeb threw himself on the cougar, just as it jumped from the rock.  They hit each other in mid-air and both fell, The cougar was on Jeb in a flash, fotgeiting about Tom, which was what Jeb wanted.Cougars are not as big as most people think and a determined man stands a chance, even with just his fists.  As the cougar’s claws(爪子)got into his left shoulder, Jeb swung his fist at its eyes and hit hard.  The animal howled（吼叫）and put its head back. Jeb followed up with his other fist.  Then out of the corner of his eye. Jeb saw Tom.  The boy was running back to help his father.“Knife, Tom,” shouted Jeb.The boy ran to his father’s bag, while Jeb started shouting as well as hitting, to keep the cougar’s attention away from Tom.  Tom got the knife and ran over to Jeb. The cougar was moving its head in and out, trying to find a way through the wall Jeb was making out of his arms.  Tom swung with the knife, into the cougar’s back.  It howled horribly and ran off into the mountains.The whole fight had taken about thirty seconds.52.  Why did Jeb pull his jacket open when he saw the cougar?A.  To get ready to fight   B.  To frighten it awayC.  To protect the boy      D.  To cool down53.  What do we know about cougars?A.  They are afraid of noises      B.  They hesitate before they hitC.  They are bigger than we think D.  They like to attack running people54.  How did Jeb try to hold the cougar’s attention?A.  By keeping shouting and hitting    B.  By making a wall out of his armsC.  By throwing himself on the cougar D.  By swinging his fists at the cougar’s eyes55. Which of the following happened first?A.  The cougar jumped from the rock B.  Tom struggled free of his fatherC.  Jeb asked Tom to get the knife     D.  Jeb held Tom across his body