We wear sunglasses to protect our eyes _____________ the sun.

    There is a man and he calls the police when he loses a pet. He a lways asks the police to help him look for it.

    “I lost my pet bird，”he tell the police one day.“She can sing songs. Can you find her for me?”

    “I'm sorry，”the policeman says.“It isn't our job（工作）to look for birds. If you leave a window open in your house，the bird may come back.”

    Another time，the man calls the police and says，“I lost my cat. （A）你能帮我找到他吗？He can  talk. ”

    “I'm sorry，”the policeman says.“（B）It isn't our job to look for cats. You should put the telephone down quickly. Maybe（也许）he is calling you now and tells you where he is. ”

鱼在水中游动时，即使视力不好，也能顺利躲过礁石，是因为（  ）

设计要求如下：

A.安装支架后的警示牌能稳定地摆放在地面上，警示牌的总高度不低于500mm

B.安装支架后的警示牌能放入内部空间为500mm×400mm×30mm的盒中

   请根据上述设计要求和警示牌的尺寸，完成以下任务：