皮皮学，免费搜题
登录
搜题
【单选题】
逆压梯度的存在是边界层发生分离的必要条件，而分离的真正产生要看边界层内流体是否发生倒流。在具有相同外流的逆压梯度条件下，边界层中哪种流态不容易发生分离?
A.
层流边界层；
B.
湍流边界层。
拍照语音搜题，微信中搜索"皮皮学"使用
参考答案：
参考解析：
知识点：
.
..
皮皮学刷刷变学霸
举一反三
【单选题】作功顺序为 1-3-4-2的发动机,当第三缸处压缩行程时,那么第一缸处在 ( )行程.
A.
进气
B.
压缩
C.
作功
D.
排气
查看完整题目与答案
【单选题】作功顺序1-3-4-2的发动机，在第三缸活塞压缩上止点时，可以检查调整哪些气门间隙。
A.
3缸的进、排气门和4、2缸的进气门
B.
1、4缸的进气门和2缸的排气门
C.
3缸的进、排气门和4缸的排气门和1缸的进气门
D.
1缸的进、排气门和4缸的排气门和2缸的进气门
查看完整题目与答案
【单选题】根据城建税规定，下列说法正确的是（ ）
A.
自 2010 年 12 月 1 日起，外商投资企业应依法缴纳城建税
B.
进口环节增值税纳税人同时也是城建税纳税人
C.
城建税实行行业差别税率
D.
城建税的计税依据是纳税人缴纳的增值税、消费税以及滞纳金和罚款
查看完整题目与答案
【单选题】In some countries in which there is very little rain at any time, the farmers have to water their fields. Irrigation is easy enough if there is a great river near the crops and if there is plenty of w...
A.
the problems caused by river water
B.
the necessity to irrigate the field
C.
the water shortage in some countries
D.
the canals carrying water to fields
查看完整题目与答案
【单选题】作功顺序 1-3-4-2 的发动机,在第三缸活塞压缩上止点时,可以检查调整( )气门间隙
A.
3 缸的进、排气门和 4 、 2 缸的进气门
B.
1 、 4 缸的进气门和 2 缸的排气门
C.
3 缸的进、排气门和 4 缸的排气门和 1 缸的进气门
D.
1 缸的进、排气门和 4 缸的排气门和 2 缸的进气门
查看完整题目与答案
【简答题】In some countries in which there is very little rain at any time, the farmers have to irrigate their fields. Irrigation is easy enough if there is a great river near the crops, and if there is plenty ...
查看完整题目与答案
【单选题】According to the passage， what did the farmers have to do with the coming of mechaniza-tion of agriculture? 查看材料
A.
Many of them had to leave their farmland for industrial centers．
B.
They stuck to their farm work．
C.
They refused to use machines．
D.
They did their best to learn how to use the machines．
查看完整题目与答案
【单选题】根据城建税规定，下列说法正确的是( )
A.
城建税的计税依据是纳税人缴纳的增值税、消费税以及滞纳金和罚款
B.
自2010年12月1日起，外商投资企业应依法缴纳城建税
C.
城建税实行行业差别税率
D.
进口环节增值税纳税人同时也是城建税纳税人
查看完整题目与答案
【单选题】To label their product as organic， farmers have to obtain a certificate showing that no __________chemicals have been used to kill pests on the farm for two years.
A.
tragic
B.
toxic
C.
notorious
D.
nominal
查看完整题目与答案
【单选题】According to the passage, what did the farmers have to do with the coming of mechanization of agriculture?
A.
Many of them had to leave their farmland for industrial centers.
B.
They stuck to their farm work.
C.
They refused to use machines.
D.
They did their best to leam how to use the machines.
查看完整题目与答案
相关题目：
【单选题】作功顺序为 1-3-4-2的发动机,当第三缸处压缩行程时,那么第一缸处在 ( )行程.
A.
进气
B.
压缩
C.
作功
D.
排气
查看完整题目与答案
【单选题】作功顺序1-3-4-2的发动机，在第三缸活塞压缩上止点时，可以检查调整哪些气门间隙。
A.
3缸的进、排气门和4、2缸的进气门
B.
1、4缸的进气门和2缸的排气门
C.
3缸的进、排气门和4缸的排气门和1缸的进气门
D.
1缸的进、排气门和4缸的排气门和2缸的进气门
查看完整题目与答案
【单选题】根据城建税规定，下列说法正确的是（ ）
A.
自 2010 年 12 月 1 日起，外商投资企业应依法缴纳城建税
B.
进口环节增值税纳税人同时也是城建税纳税人
C.
城建税实行行业差别税率
D.
城建税的计税依据是纳税人缴纳的增值税、消费税以及滞纳金和罚款
查看完整题目与答案
【单选题】In some countries in which there is very little rain at any time, the farmers have to water their fields. Irrigation is easy enough if there is a great river near the crops and if there is plenty of w...
A.
the problems caused by river water
B.
the necessity to irrigate the field
C.
the water shortage in some countries
D.
the canals carrying water to fields
查看完整题目与答案
【单选题】作功顺序 1-3-4-2 的发动机,在第三缸活塞压缩上止点时,可以检查调整( )气门间隙
A.
3 缸的进、排气门和 4 、 2 缸的进气门
B.
1 、 4 缸的进气门和 2 缸的排气门
C.
3 缸的进、排气门和 4 缸的排气门和 1 缸的进气门
D.
1 缸的进、排气门和 4 缸的排气门和 2 缸的进气门
查看完整题目与答案
【简答题】In some countries in which there is very little rain at any time, the farmers have to irrigate their fields. Irrigation is easy enough if there is a great river near the crops, and if there is plenty ...
查看完整题目与答案
【单选题】According to the passage， what did the farmers have to do with the coming of mechaniza-tion of agriculture? 查看材料
A.
Many of them had to leave their farmland for industrial centers．
B.
They stuck to their farm work．
C.
They refused to use machines．
D.
They did their best to learn how to use the machines．
查看完整题目与答案
【单选题】根据城建税规定，下列说法正确的是( )
A.
城建税的计税依据是纳税人缴纳的增值税、消费税以及滞纳金和罚款
B.
自2010年12月1日起，外商投资企业应依法缴纳城建税
C.
城建税实行行业差别税率
D.
进口环节增值税纳税人同时也是城建税纳税人
查看完整题目与答案
【单选题】To label their product as organic， farmers have to obtain a certificate showing that no __________chemicals have been used to kill pests on the farm for two years.
A.
tragic
B.
toxic
C.
notorious
D.
nominal
查看完整题目与答案
【单选题】According to the passage, what did the farmers have to do with the coming of mechanization of agriculture?
A.
Many of them had to leave their farmland for industrial centers.
B.
They stuck to their farm work.
C.
They refused to use machines.
D.
They did their best to leam how to use the machines.
查看完整题目与答案