解析：D　后文的内容是作者"意识到"的内容。

　　17．A.dreams B．qualities

　　C．concerns D．experiences

　　解析：B　前面的这些词语是人类所共有的"品质"。

　　18．A.boring B．humorous

　　　　C．great D．serious

　　解析：C　根据文章开头说的"不到长城非好汉"可知，作者不知道自己从长城回来是不是变成了"好"汉。

　　19．A.trip B．country

　　　　C．vacation D．risk

　　解析：A　这里是指爬长城的这次"旅行"。

　　20．A.but B．as

　　　　C．unless D．so

　　解析：A　根据语境可知前后是转折关系，故选but。

　　Ⅳ.语法填空

　　The question "Who is your hero？"is a difficult one to answer. So many people have done heroic things 1.________ it is hard to choose just one. In addition, there is 2.________ (many) than one type of hero.

　　First, we have heroes in popular culture: in books, films and cartoons, etc. Superman and Batman are two famous comic book heroes, the latter of 3.________ has no superpowers, and instead has to rely on 4.________ (he) own skills. Of course, there are many real­world people who are 5.________ (know) around the world for their heroic deeds. People like Nelson Mandela, Mohandas Gandhi and Martin Luther King 6.________ (consider) to be heroes. They were brave and loyal to their people. There are also unsung heroes. They 7.________ (usual) do good things － yet don't expect to receive praise for their actions. Unsung heroes are everywhere － teachers, firemen, police officers, soldiers, doctors.

　　No matter what type of hero these people are, they all have something 8.________ common. They often have to overcome many difficulties 9.________ (achieve) their dreams. They do things for the benefit of society without 10.________ (seek) any reward for their actions.

　　1．解析：that　考查连词。so...that引导结果状语从句，意为"如此......以至于"。

　　2．解析：more　考查固定结构。more than one...意为"不止一......"。

　　3．解析：whom　考查关系代词。此处为"介词＋关系代词"引导的非限制性定语从句，修饰先行词heroes，因设空处在从句中作介词of的宾语，故填whom。

　　4．解析：his　考查代词。设空处作定语修饰skills，应用形容词性物主代词，故填his。

　　5．解析：known　考查形容词作表语的用法。设空处作表语，表示"闻名的"，故填known。

　　6．解析：are considered　考查一般现在时的被动语态。People与consider之间是被动关系，且此处表示客观事实，故填are considered。

　　7．解析：usually　考查副词。设空处作状语修饰do，故填usually。

　　8．解析：in　考查介词。have...in common意为"有共同之处"。

　　9．解析：to achieve　考查不定式作状语的用法。设空处表目的，因They与achieve之间是逻辑上的主谓关系，故填to achieve。

　　10．解析：seeking　考查动词­ing形式作宾语的用法。设空处作介词without的宾语，且They与seek之间是逻辑上的主谓关系，故填seeking。