【单选题】听力原文:New York City: The United States National Weather Service says that the huge winter storm has dumped some 68.3 centimeters of snow in Central Park, making it the worst blizzard to hit New York Ci...
【简答题】试写出光吸收定律的数学表达式,并说明各符号的含义。
【单选题】下列四个命题中真命题是( ) ①“若xy=1,则x、y互为倒数”的逆命题②“面积相等的三角形全等”的否命题③“若m≤1,则方程x 2 -2x+m=0有实根”的逆否命题④“若A∩B=B,则A?B”的逆否命题.
【单选题】This passage says that the work of removing stones______.
A.
is usually done during the winter
B.
was more difficult before machines were used
C.
must be done again and again
D.
is an interesting job children enjoy doing
【简答题】补全单词。 ( ) 1. sc__ __f ( ) 2. wint__ __ ( ) 3. t__ __ch ( ) 4. spr__ __ __ ( ) 5. skat__ ( ) 6. w__ __d ( ) 7. mi__ __ens ( ) 8. less__ __ ( ) 9. sk__ ( ) 10. __...
【单选题】设 为两条直线, 为两个平面,下列四个命题中真命题是 ( )
【单选题】已知m、n是两条不重合的直线,α、β、γ是三个两两不重合的平面,则下列四个命题中真命题是 ( )
【单选题】wint ar underhand word “dishevcled mean?
【单选题】下列四个命题中真命题是( )
B.
过空间任一点与两条异面直线都垂直的直线有且只有一条
C.
底面各边相等、侧面都是矩形的四棱柱是正四棱柱