皮皮学，免费搜题
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搜题
【简答题】
计算下列程序片断的时间代价： int i=1； while(i<=n){ int j=1； while(j<=n){ int k=1； while(k<=n){ printff('i=％d，j=％d，k=％d＼n'，I,j，k)； k=k+1； } j=j+1； } i=i+1； }
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皮皮学刷刷变学霸
举一反三
【单选题】I a letter from him since he left.
A.
didn't receive
B.
haven't got
C.
didn't have
D.
haven't heard
【简答题】必须把这一点说清楚。(passive voice)
【单选题】I a letter from my sister yesterday.
A.
receive
B.
received
C.
receives
D.
to receive
【简答题】Last week I a letter from my best friend.
【简答题】I a letter from my brother last week.(received/took )