在过流断面面积和其它条件相同时,流体流过椭圆管比流过圆管时的沿程阻力损失大。
参考答案:对
This is my classroom. It is not very big, but it is very nice. There are two blackboards on the wall, but there aren't any pictures. There is a clock on the front(前面的) wall. The map of the world is on the wall, too. There is a computer in the teacher's desk. You can't see it. There are forty students in my class, eighteen girls and twenty-two boys. There are forty desks and chairs for us. Miss Chen is our English teacher. Her English is very good. We all like her class.
小题1:There _____ pictures on the wall.
A. are some B. aren’t any C. are two
小题2:The _____ is on the front wall.
A. map B. clock C. computer
小题3:There are _____ girls in the class.
A. 40 B. 22 C. 18
小题4:_____ English is very good.
A. My B. Their C. Miss Chen’s
小题5:–How many computers are there in the classroom? –_____.
A. One. B. Two. C. Sorry, I don’t know.
新中国成立后,为加快西藏地区经济发展和社会进步,党和政府做的努力包括
①和平解放西藏
②进行民主改革,废除封建农奴制
③修筑了三条入藏公路和青藏铁路
④建立西藏自治区
⑤设立了经济特区
A.①②③
B.①③④
C.①②③④
D.①②③④⑤