问题
完形填空
Erik was a fourteen-year-old boy. He thought he was a young man but his parents didn’t think so. They told him, “When you begin to think about 1 others, you’ll be a young man.” One morning, his parents gave Erik 2 money to buy hamburgers at a store. He saw an old man there. The old man looked very 3 . Erik went up to him and found that the old man had lost his money and hadn’t had 4 for his breakfast. Erik took the old man to the nearest restaurant. But the man ordered only a glass of water for 5 . Erik felt sorry for him, so he asked the waiter to 6 the old man some bread and a cup of coffee. The old man was so 7 that he ate up all the food very soon. After that, the old man told Erik that he would never forget 8 kindness. Erik was very pleased when he heard the old man said, “You are a very good young man.” 9 their surprise, the food was a present because 10 day was the birthday of the boss.
|
答案
小题1:B
小题2:C
小题3:C
小题4:B
小题5:D
小题6:B
小题7:C
小题8:D
小题9:B
小题10:A
小题1:此题重点考查固定短语think about doing sth表示考虑做某事。当你学会为别人考虑时，你就成了男子汉了。故选B。
小题2:此题考查固定结构give sb something表示给某人某物，因money是不可数名词，few和a few，may都是用来修饰可数名词的复数形式故用some来修饰，故选C。
小题3:此题考查形容词，根据下文内容提示，可知这位老人非常饥饿，故应看上去应是非常虚弱，故选C。
小题4:此题考查名词，根据上文内容的提示，老人丢了钱，于是早餐没吃任何东西，故选anything。
小题5:此题考查人称代词，根据语境可知选择himself表示老人只给自己要了一杯水。
小题6:此题考查固定结构ask sb to do sth表示让某人做某事；把东西拿来要用动词bring故用B。
小题7:此题考查形容词，根据语境可知老人非常饥饿，故选hungry。
小题8:此题考查物主代词，因Eric是男孩，故选his。
小题9:此题考查固定短语to one’s surprise表示让某人惊奇的是，故选B。
小题10:此题考查指示代词，根据语境可知选择that，因为那天是饭店老板的生日，应是免费的。
需要m*n*p次乘法运算。
三个矩阵相乘为例，若按（A1*A2）*A3计算，则需要进行10*100*5+10*5*50=7500次乘法运算；若按A1*（A2*A3）计算，则需要进行100*5*50+10*100*50=75000次乘法运算。可见不同的计算顺序对计算量有很大的影响。矩阵链乘问题可描述为：给定n个矩阵，矩阵Ai的维数为
，其中i=1，2，…，n。确定一种乘法顺序，使得这n个矩阵相乘时进行乘法的运算次数最少。
