【单选题】早在1977年联合国就向全世界发出警告,继石油危机之后的下一个危机便是( )危机
【单选题】A: How’s your vocation?
C.
Quite good, what about you?
D.
Yes, fine, how are you, then?
【单选题】--- How is your vocation?-----____________
【判断题】已知L[f1(t)]=F1(s),L[f2(t)]=F2(s),k1和k2为常数,则L[k1f1(t)+k2f2(t)]=k1F1(s)+k2F2(s).
【单选题】Have you ___ your parents of your plan for the winter vocation?
【单选题】Make authorship your __________, not your vocation.
【单选题】已知F(s)=L[f(t)],若F(s)= ,则f(t)| t =?( )
【单选题】已知 L[f(t)]=F(s),则 L[f (3) ( t )] = :
【简答题】— What’s your plan for the summer vocation?