工程上常用爆破的方法开山劈岭,设某工人师傅在钻孔内装好炸药后,用一根96 cm

题型:计算题

问题:

工程上常用爆破的方法开山劈岭,设某工人师傅在钻孔内装好炸药后,用一根96 cm 的引火线引燃炸药,如果引火线燃烧速度是0.8 cm/s ,点火人点燃引火线后以5 m/s 的速度跑开, 他能不能在爆炸前跑到离点火处500 m 远的安全地带?

考点:速度的计算
题型:计算题

重度二尖瓣狭窄的瓣口面积应()

A.<4.0cm2

B.2.0~4.0cm2

C.<1.5cm2

D.<1.0cm2

E.<0.75cm2

题型:计算题

影响第一心音强度变化的因素不包括()

A.心肌收缩力

B.心室充盈度

C.瓣膜弹性

D.瓣膜位置

E.心室壁厚度

题型:计算题
Mary was seven years old. Her parents recently moved to a new town, and so Mary was going to a 36   school, which was a few kilometers from the house they lived in now. A school bus going around picked up 37 every morning and brought them back to their  38  every afternoon, and as both of Mary’s parents  39 to go to work, she always went on this bus.
Mary’s parents always 40  their alarm clock for seven o’clock so that none of them would be 41   . But one morning the alarm  42  to go off, and it was not until a quarter past eight that Mary’s mother suddenly 43  , looked at the clock and said, “What’s ever happened to that clock?” and then 44   into Mary’s room to wake her up.
“I’m sorry, dear,” she said, “ 45 you’ll have to wash and dress very quickly, have an even  46 breakfast and then I’ll  47  you to school on my way to the office.”
“But how can you find the   48, Mum?” Mary said, “You’ve been to school only once.”
“Yes,” her mother answered, “but you’ve done the   49   several times now on the bus, so you can be my guide to get there, can’t you?”
“Oh, yes,” said Mary, “I suppose so.” She washed, and  50  and had a quick breakfast, and then they set off. Mary told her mother to turn each time they came to a place she 51  .In this way she made her mother drive round most of the town   52  they got to her school. When they arrived, her mother saw that it was not really very far from her house.
“Why ever did you make me go such a long way round, Mary, instead of the most    53    way?” her mother asked her.
“Well, Mum,” answered Mary, “it was because I didn’t know   54  else to get here. That’s the way our bus always goes to   55   the other children to school.
小题1:
A.bigB.niceC.differentD.distant
小题2:
A.pupilsB.teachersC.parentsD.passengers
小题3:
A.officesB.townsC.classroomsD.homes
小题4:
A.seemedB.hadC.refusedD.used
小题5:
A.foundB.setC.cleanedD.fixed
小题6:
A.lateB.ready C.lazyD.asleep
小题7:
A.startedB.stoppedC.failedD.continued
小题8:
A.stood upB.stayed upC.put upD.woke up
小题9:
A.rushedB.steppedC.escapedD.jumped
小题10:
A.butB.andC.soD.then
小题11:
A.laterB.quickerC.easierD.heavier
小题12:
A.bringB.fetchC.leaveD.drive
小题13:
A.truthB.busC.wayD.guide
小题14:
A.homeworkB.shoppingC.tripD.reading
小题15:
A.roseB.dressedC.moveD.showed
小题16:
A.wonderedB.realizedC.recognizedD.designed
小题17:
A.unlessB.afterC.ifD.before
小题18:
A.comfortableB.helpfulC.importantD.direct
小题19:
A.howB.whenC.what D.which
小题20:
A.look forB.pick upC.drop byD.deal with
题型:计算题

抗维生素D佝偻病是由位于X染色体的显性致病基因决定的一种遗传病,这种疾病的遗传特点之一是()

A.男患者与女患者结婚,其女儿正常

B.男患者与正常女子结婚,其子女均正常

C.女患者与正常男子结婚,儿子正常女儿患病

D.患者的正常子女不携带该患者传递的致病基因

题型:计算题

硅-二氧化硅系统中含有的最主要而对器件稳定性影响最大的离子是()。

A.钠

B.钾

C.氢

D.硼

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