更多"A. At a restaurant. B. At a store"的相关试题:
[简答题]
5(a²b—ab²)—(ab²+3a²b) 其中a=二分之一 b=负一
小王种植了大豆玉米和芋头共200m² 其中大豆的面积是(x-2)m² 玉米的种植面积是大豆的两倍 求芋头的种植面积
已知A=X³+2y³—xy²,B=-Y+x³+2xy²,其中x=三分之一 y=2 求A-B的值
[简答题]求曲面2x²+3y²+4z²=81上平行于平面2x+3y+4z=18的切平面方程。
[单项选择]α²+β²的最小值是1/2。()
(1)α与β是方程x²-2ax+(a²+2a+1)=0的两个实根
(2)αβ=1/4
A. 条件(1)充分,但条件(2)不充分
B. 条件(2)充分,但条件(1)不充分
C. 条件(1)和(2)单独都不充分,但条件(1)和条件(2)联合起来充分
D. 条件(1)充分,条件(2)也充分
E. 条件(1)和(2)单独都不充分,条件(1)和条件(2)联合起来也不充分
[单项选择]α²+β²的最小值是1/2。()
(1)α与β是方程x²-2ax+(a²+2a+1)=0的两个实根
(2)αβ=1/4
A. 条件(1)充分,但条件(2)不充分
B. 条件(2)充分,但条件(1)不充分
C. 条件(1)和(2)单独都不充分,但条件(1)和条件(2)联合起来充分
D. 条件(1)充分,条件(2)也充分
E. 条件(1)和(2)单独都不充分,条件(1)和条件(2)联合起来也不充分
[单项选择]Ocean water plays an indispensable role in
supporting life. The great ocean basins hold about
300 million cubic miles of water. From this vast
Line amount, about 80,000 cubic miles of water are
(5) sucked into the atmosphere each year by evapora-
tion and returned by precipitation and drainage to
the ocean. More than 24,000 cubic miles of rain
descend annually upon the continents. This vast
amount is required to replenish the lakes and
(10) streams, springs and water tables on which all
flora and fauna are dependent. Thus, the hydro-
sphere permits organic existence.
The hydrosphere has strange characteristics
because water has properties unlike those of any
(15) other liquid. One anomaly is that water upon
freezing expands by about 9 percent, whereas
most liquids contract on cooling. For this reason,
ice floats on wat
A. describe the properties and uses of water
B. illustrate the importance of conserving water
C. explain how water is used in commerce and industry
D. reveal the extent of the earth’s ocean masses
E. (E) compare water with other liquids
[填空题]Competition for grades and other pressures are supposed to take the responsibility of ______.
[简答题]Pronom adverbalVous allez faire des courses au supermarché Je peux _____ accompagner.
A. A.vous l’
B.les y
C.vous y
D.vous en
[单项选择]曲线ax²+by²=1通过4个定点。()
(1)a+b=1
(2)a+b=2
A. 条件(1)充分,但条件(2)不充分
B. 条件(2)充分,但条件(1)不充分
C. 条件(1)和(2)单独都不充分,但条件(1)和条件(2)联合起来充分
D. 条件(1)充分,条件(2)也充分
E. 条件(1)和(2)单独都不充分,条件(1)和条件(2)联合起来也不充分
[简答题]验证在整个axy平面内(2xy+3x²+1)dx+(x²+2y-3)dy是某个二元函数u(x,y)的全微分,并求这样的一个u(x,y)。
[单项选择]方程x²+mxy-6y²-10y-4=0的图形是两条直线。()
(1)m=7
(2)m=-7
A. 条件(1)充分,但条件(2)不充分
B. 条件(2)充分,但条件(1)不充分
C. 条件(1)和(2)单独都不充分,但条件(1)和条件(2)联合起来充分
D. 条件(1)充分,条件(2)也充分
E. 条件(1)和(2)单独都不充分,条件(1)和条件(2)联合起来也不充分