指令SAR可用来______除2，而指令SHR则可用来______除2。

已知三角形两边长分别为2和9,第三边的长为二次方程x²-14x+48=0的一根,则这个三角形的周长为(   )

A．11

B．17

C．17或19

D．19

阅读理解。

     Some years ago on a hot summer day in south Florida a little boy decided to go for a swim in the old

swimming hole behind his house. In a hurry to dive into the cool water, he ran out of the back door,

leaving behind shoes, socks, and shirt as he went.

     He flew into the water, not realizing that as he swam toward the middle of the lake, a crocodile was

swimming toward him. His mother in the house was looking out of the window and saw the two. In great

fear, she ran toward the water, shouting to her son as loudly as she could. Hearing her voice, the little

boy became alarmed and made a U-turn to swim to his mother. It was too late. Just as he reached her,

the crocodile reached him. From the shore, the mother grabbed her little boy by the arms just as the

crocodile snatched his legs. That began an incredible tug-of-war between the two. The crocodile was

much stronger than the mother, but the mother was much too passionate to let go. A farmer happened

to drive by, heard their screams, raced from his truck, took aim and shot the crocodile.

     Remarkably, after weeks and weeks in the hospital, the little boy survived. His legs were extremely

scarred by the attack of the animal. And, on his arms, were deep scratches where his mother's fingernails

dug into his flesh in her effort to hang on to the son she loved.

     The newspaper reporter, who interviewed the boy, asked if he would show him his scars. The boy

lifted his legs. And then, with obvious pride, he said to the reporter, "But look at my arms. I have great

scars on my arms, too. I have them because my Mom wouldn't let go. "

      Never judge another person's scars, because you don't know how they were made.

1. By saying "But look at my arms. I have great scars on my arms, too" in paragraph 4,the boy really

    wants to show__________.

A. how deep the scars made by the crocodile were

B. what a brave and courageous boy he was

C. how many scars and scratches he had

D. how great and beloved his mother was

2. Hearing Mother's shouts, the boy______. 

A. remained in the middle at a loss    

B. didn't stop swimming forwards

C. swam back towards the shore

D. was ready to fight the crocodile

3. Which of the following statements is true according to the text?

A. A crocodile attacked him when the boy and his mother were swimming.

B. The crocodile bit the arms of the boy when it reached him.

C. There is always an interesting story behind every scar.

D. It was the farmer who shot the crocodile.

4. Which of the following will be the best title for the text?

A. Scars of Love                  

B. Women Hold up Half the Sky

C. A Terrible Experience              

D. Don't Judge by Appearances

《钢轨伤损编码》第五层数字代表伤损的主要原因。

纳税人不论当期是否发生纳税义务，除经税务机关批准外，均应按规定办理纳税申报。

肺炎伴大叶实变的视诊特点是

A．呼吸加深

B．以上都不是

C．呼吸增快

D．气短

E．呼吸急促、变浅、鼻翼扇动