七个句子,麻烦大家看看哪句有错误,有的话请改正,谢谢

题目

七个句子,麻烦大家看看哪句有错误,有的话请改正,谢谢
①.if you didn't learn hard,you won't get the success
②.whatever you do,you should try your best
③.whatever difficult the task is,we will try our best to complete it on time
④.althogh child he is,he knows how living and learning
⑤.we opened all window because it is a good weather
⑥.he thinks it is important for making a preparation before exam
⑥-2.he thinks it is important to make a preparation before exam
⑦i want to buy the english dictionary very much,but i'm lack of the money for buying it

答案

①.if you didn't（don't) learn hard,you won't get the success
主将从先
②.whatever you do,you should try your best 对
③.whatever difficult the task is,we will try our best to complete it on time 对
④.althogh child he is,he knows how living and learning---how to live and learn
⑤.we opened all window because it is a good weather---it was good weather
⑥.he thinks it is important for making a preparation before exam
is important to make
⑥-2.he thinks it is important to make a preparation before exam 对
⑦i want to buy the english dictionary very much,but i'm lack of the money for buying it 对