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【简答题】
焊条药 ,在焊接过程中起着极为重要的作用。首先,它可以起到积极 作用,利用药皮熔化放出的 和形成的 ,起机械 作用,防止有害气体侵入熔化金属;其次可以通过熔渣与熔化金属 ,去除 ,添加 的合金元素,起到冶金处理作用,使焊缝获得合乎要求的力学性能;最后,还可以改善 性能,使电弧稳定、飞溅小、焊缝成形好、易脱渣和熔敷效率高等。
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【简答题】Governments use fiscal policy to promote social, economic and security agendas. The theoretical economic effects of a fiscal policy can take many forms, only some of which are part of a policy's origi...
【单选题】在单三角锁中，观测到一个三角形的三个内角值分别为58°28′30″，42°29′56″，79°01′46″，则在该三角形中，其内角改正数值为（）
A.
+4″
B.
-4″
C.
+3″
D.
-3″
【单选题】在单三角锁中,观测到一个三角形的三个内角分别为58°28′20′′,42°29′56′′,79°01′46′′,则在三角形中,其内角改正数值为()。
A.
﹢4″
B.
﹣4″
C.
﹢3″
D.
﹣3″
【单选题】—You look unhappy. What's up? —I lost my MP4 0n the bus yesterday. It ________me $ 50. [ ]
A.
paid
B.
cost
C.
spent
D.
took
【单选题】小李和小张是室友，小李不喜欢打扫卫生间，小张答应打扫卫生间但前提是小李必须去打扫卧室，这里体现了哪个经济原则：
A.
他们俩的行为体现的是“边际收益”原则
B.
小张和小李从这次分工劳动中并没有获得更大的价值
C.
小李虽然没有打扫卫生间，但是却必须去打扫卧室，所以，小李并没有得到什么好处
D.
小李和小张从劳动分工和交换中都获得了好处
【多选题】Like any theory of importance, that of social or cultural anthropology was the work of many minds and took on many forms. Some, the best known of its proponents, worked on broad areas and attempted to...
A.
Social anthropology concerns itself with broad areas while cultural anthropology concerns itself with specific aspects of culture.
B.
Cultural anthropologists, also known as social anthropologists, may work in either broad or restricted areas.
C.
Cultural anthropology is a new field of study.
D.
Any important area of study requires the work of many minds and is therefore likely to have different approaches.
E.
The best-known people in cultural anthropology attempted to describe the development of human civilization.
【简答题】设函数f（x）= 3 sin2x+cos2x+1 （Ⅰ）求函数f（x）的最小正周期； （Ⅱ）求函数f（x）的增区间 （Ⅲ）当x∈[- π 6 ， π 3 ]时，求函数f（x）的最大最小值并求出相应的x的值．
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