At last we decided _____ the new plan. [ ]
A. on
B. in
C. with
D. for
答案：A
根据句意、首字母、或中英文提示完成单词。
1. 1st J_____ is New Year's Day.
2. The tigers' t_____ are very sharp.
3. They do morning _____ (早操) at 9.25 every day.
4. September 10th is T_____ Day.
5. It's _____ (not easy, hard) for me to finish it in an hour.
对于给出的一组权w=10，12，16，21，30，通过哈夫曼算法求出的扩充二叉树的带权外部路径长度为（）。
A. 89
B. 189
C. 200
D. 300
