【简答题】A.They do not harm anyone. B.They usually look more frightening. C.They cause damage to buildings or bridge. D.They are much less exciting than in reality.
【单选题】Winning is usually a cause for celebration, may not be so for US president Barack Obama, won the Nobel Peace Prize on October 9.
【单选题】下列关于系统软件的三条叙述中,正确的是( )
【单选题】下列关于系统软件的四条叙述中,正确的是_____
【单选题】Things made by hand are usually more expensive than _ produced in factories.
【简答题】. 微分方程 y'-2xy=0 的通解是 . 求微分方程y'+y = 的通解 求微分方程y'+y =0的通解 求微分方程xy'-ylny=0的通解. 已知函数 ,求 求 求
【简答题】计算(1) 求出 的通解 ; (2)求出 的一个特解; (3)求出 的通解.
【单选题】( )Usually you will not get a shockBy touching the electric ray in one place onlyBe.cause__________.
A.
a torped0’s electric cells contain more than one electricDlates
B.
to complete the circuit,you have to touch the fish in twoDlaces
C.
the current in one place is not strong enough to give a shock
D.
the fish’s electric cells are filled with jelly-like substance