假定英语课上老师要求同桌之间交换修改作文，请你修改你同桌写的以下作文．文中共有10处语言错误，每句中最多有两处．错误涉及一个单词的增加、删除或修改．增加：在缺词处加一个

Question

假定英语课上老师要求同桌之间交换修改作文，请你修改你同桌写的以下作文．文中共有10处语言错误，每句中最多有两处．错误涉及一个单词的增加、删除或修改．
增加：在缺词处加一个漏字符号（∧），并在其下面写出该加的词．
删除：把多余的词用斜线（/）划掉．
修改：在错的词下划一横线，并在该词下面写出修改后的词．
注意：每处错误及修改均仅限一词；只允许修改10处，多者（从第11处起）不计分．
As you know it，food shortages have hit many countries in the world and even cause social unrest in some areas．But who is responsible for the current world food crisis？First，annual world grain output has declined because climate change．Then lots of farmland have been lost due to the rapid development of industry and urbanization．Then how should we do to deal with the problem？On one hand，we should focus on the environmental protection or improve the ecology．On other hand，strict measures should be taking to protect farmland．And for the moment，I think，we should study hardly to develop sciences and solve the food shortage in the future．

Answer 1

As you know it，food shortages have hit many countries in the 
world and even cause social unrest in some areas．But who is 
responsible for the current world food crisis？First，annual 
world grain output has declined because∧climate change．Then 
lots of farmland have been lost due to the rapid development of
 industry and urbanization．Then how should we do to deal with 
the problem？On one hand，we should focus on the environmental 
protection or improve the ecology．On∧other hand，strict measures 
should be taking to protect farmland．And for the moment，I think，
we should study hardly to develop sciences and solve the food shortage 
in the future．
详
1．去掉it   考查固定表达    As you know意为：正如你所知道的；故去掉it．
2．cause改成caused   考查连词and的用法    本句是由and连接的具有同一个主语food shortages 的两个句子，因此and前后的两个谓语动词在形式上应保持一致，而后面句子可以省略主语food shortages 以及助动词have；故用caused．
3．在because后加 of   考查连词because与复合介词because of的区别     because是连词，其后接原因状语从句或回答以why开头的问句； 而because of是复合介词，其后接名词、代词或动名词，或者what引导的名词性从句；此处之后为：名词短语climate change；故在because后加 of．
4．have改成has    考查主谓一致    由于此处的主语lots of farmland 为不可数名词，故谓语动词应使用第三人称单数形式；故用has．
5．how改成what   考查句意理解以及特殊疑问词   本句的意思是：那么我们该怎么处理这个问题呢？疑问副词how在句中作状语，疑问代词what在句中作主语，宾语，表语或定语；由于此处在句中作宾语，而不是状语；故用what．
6．or 改成 and   考查句意理解以及连词    本句的意思是：我们应将重点放在环境保护以及改善生态环境上；此处表示并列，而非选择关系；故用and．
7．other之前加the   考查固定搭配   on one hand…，on the other hand…意为：一方面…，另一方面…；故在other之前加the．  
8．taking改成taken   考查情态动词的被动语态     本句中的主语strict measures 与动词take构成被动关系，故此处应使用情态动词should的被动语态形式；故用taken．
9．hardly改成hard   考查副词词义辨析   hardly意为：几乎不，简直不；hard意为：努力地；此处指的是：努力学习；故用hard．
10．sciences改成science   考查不可数名词   由于science是不可数名词，其后不能加s，故用science．