10．more　考查形容词的比较级。appreciative是多音节形容词，本句表示"黑暗让他更加感激光明"，应用形容词的比较级形式，故填more。

　　Ⅳ.短文改错

　　Thanks for your concern in your letter about the smog which frequent strikes some areas of China. I'm also very worrying about such a terrible weather. It has brought much inconvenience or rather harm to people's health such as road accident, bad coughs and even lung cancers and so on.

　　It is known to all, good environment comes from careful protection. But we should do what we can protect it. I believe a small step can make a different. Try to drive less and choose air­friendly products. Only when everyone had the environmental awareness can we have a blue sky. Hope to hear from you and share my good ideas.

　　答案：

　　Thanks for your concern in your letter about the smog which strikes some areas of China. I'm also very about such terrible weather. It has brought much inconvenience or rather harm to people's health such as road ， bad coughs and even lung cancers and so on.

　　 is known to all, good environment comes from careful protection. we should do what we can protect it. I believe a small step can make a . Try to drive less and choose air­friendly products. Only when everyone the environmental awareness can we have a blue sky. Hope to hear from you and share good ideas.

　　难项分析：

　　第三处：去掉a　考查冠词。weather是不可数名词，不能和不定冠词搭配。故去掉a。

　　第七处：protect前加to　考查非谓语动词。句意：所以我们应该尽我们所能去保护它。此处用动词不定式作目的状语。故在protect前加to。

　　第八处：different→difference　考查固定搭配。make a difference为固定搭配，意为"有影响，起作用"。