巯嘌呤的作用机制是() A.通过使腺苷酸和鸟苷酸缺乏而阻碍DNA合成 B.通过损伤D

题型:单项选择题

问题:

巯嘌呤的作用机制是()

A.通过使腺苷酸和鸟苷酸缺乏而阻碍DNA合成

B.通过损伤DNA并阻碍其修复而抑制DNA合成

C.通过积聚三磷酸核苷酸而抑制细胞的DNA合成

D.通过使脱氧胸苷酸缺乏而造成DNA合成障碍

E.通过减少四氢叶酸生成而中断DNA和RNA合成

考点:西药执业药师药学专业知识(一)西药执业药师药学专业知识(一)
题型:单项选择题

基牙向缺隙方向倾斜时所画出的观测线为()。

A.Ⅰ型观测线

B.Ⅱ型观测线

C.Ⅲ型观测线

D.Ⅳ型观测线

E.Ⅴ型观测线

题型:单项选择题

物体沿圆轨道做匀速圆周运动,则该物体[ ]

A.加速度不变

B.动能不变

C.所受合力不变

D.角速度不变

题型:单项选择题
People from Great Britain brought the English language to North America in the 16th and 17th centuries. And in the __36__ 300 years, there were so many___37__ in both places that now people can easily___38__ an English person from an American in the___39__ he or she talks.
Many old words___40__ in England but were kept in America.For example,300 years ago people in Great Britain got their water from something they__41__either a“faucet”,“spigot”,or a“tap”.All these words are___42__ heard in different parts of America, but only “tap”is still___43_ in England.Americans often make___44__ new words or change old ones. “Corn”is one kind of plant in America and__45__ in England.
Also, over the last three centuries the English language has___46__ thousands of new words for things that weren’t___47__ before. And often, American and English people used two__48__ names for them. A tin can is called“tin”for short in English, but a “can”in America.The word “radio”is__49__all over the world, including America.But many English people call it a “wireless”.And almost anything___50__ something to do with cars, railroads, etc.has different___51__ in British and American English.
But now American and British English may be___52__ closer together. One thing is that__ 53_ people can hear a large amount of American speech daily in___54__, on television, or from travelers. Because of this, Americans___55__ to be influencing the British more and more. So some day, English may even be the same on both sides of the Atlantic.
小题1:
A.pastB.recentC.oldestD.latest
小题2:
A.citizensB.inventionsC.changesD.advances
小题3:
A.pickB.tellC.takeD.judge
小题4:
A.voiceB.placeC.languageD.way
小题5:
A.disappearedB.stayedC.returnedD.formed
小题6:
A.saidB.talkedC.spokeD.called
小题7:
A.thenB.hardlyC.clearlyD.still
小题8:
A.necessary B.nativeC.commonD.lively
小题9:
A.ofB.intoC.upD.out
小题10:
A.anotherB.the otherC.noneD.something
小题11:
A.discoveredB.addedC.improvedD.learned
小题12:
A.acceptedB.knownC.introducedD.understood
小题13:
A.newB.shortC.differentD.surprising
小题14:
A.producedB.madeC.developedD.used
小题15:
A.havingB.bringingC.gettingD.making
小题16:
A.typesB.namesC.degreesD.parts
小题17:
A.puttingB.stayingC.livingD.growing
小题18:
A.BritishB.AmericanC.educatedD.ordinary
小题19:
A.families B.busesC.moviesD.newspapers
小题20:
A.needB.expectC.seemD.happen
题型:单项选择题

下列各项中,应计入销售费用的有( )。

A.随同商品出售不单独计价的包装物成本

B.随同商品出售单独计价的包装物成本

C.分期摊销的出租包装物成本

D.分期摊销的出借包装物成本

题型:单项选择题

当硫磺燃烧产生大量的二氧化硫,应急处理人员戴自给正压式呼吸器,穿防毒服。从()进入现场。

A、上风处

B、下风处

C、侧面

D、任意方向

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