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【多选题】
在质点系中,以下描述中哪几项是正确的?( )A.
一对相互作用力的功之和与参考系无关
B.
一对相互作用力的功之和不一定为零
C.
一对滑动摩擦力的功之和为负
D.
一对正压力的功之和不一定为零
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举一反三
【单选题】When is the Lantern Festival?
A.
It is on the 15th of the first lunar month.
B.
It is on the 15th of the eighth lunar(阴历的) month
C.
It is on the 15th of the first month.
D.
It is on the 15th of the eighth month.
【多选题】(多选题)关于交叉圆柱镜精确散光的度数,正确的做法是()。
A.
只要将交叉圆柱镜放在戴检验的柱镜前即可
B.
将交叉圆柱镜上的红点放在待检验的轴位上
C.
将交叉圆柱镜上的白点放在待检验的轴位上
D.
将交叉圆柱镜的负轴放在待检验的轴位上
E.
将交叉圆柱镜的正轴放在待检验的轴位上
【单选题】When is the Chongyang festival?
A.
It is on the ninth day of the ninth month.
B.
It is on the ninth day of the ninth lunar month.
C.
It is on the seventh day of the seventh lunar month.
D.
It is on the eighth day of the eighth lunar month.
【单选题】When is the Lantern Festival ?
A.
Before the Spring Festival Eve
B.
On the Spring Festival Eve
C.
On the Chinese New Year’s Day
D.
At the end of the Spring Festival .
【单选题】When is the spring festival?
A.
the first day of the first lunar month
B.
January 1st
C.
the fifteenth day of the first lunar month
D.
the first day of the second lunar month
【简答题】烫伤出现水疱、大叶性肺炎、疖的炎症本质分别是 、 、 。
【简答题】烫伤出现水疱、大叶性肺炎、疖的炎症本质分别为_________、_________、_________。
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