to learn a foreign language well is useful,I think(改为同义句)I think it useful to learn a foreign language well .这里的第二句话中为什么用it而不是it's

to learn a foreign language is not just want to find a foreign friend ,to learn english . to learn a foreign language well 同义句转换to learn a foreign language well 改为 I think _____ _______to learn a foreign language well. To learn a foreign language is------in our work.(help) We find ( )difficult to learn a foreign language. What I to learn a foreign language well?What ——i——to learn a foreign language well？ these student need to learn a foreign language (同义句改写) ____ ____these students to learn a foreign language To learn a foreign lauguage is necessary.同义句 ____ ____ ____ to learn a foreign lauguage. ___is very important___us__a foreign language.A.It;for;to learn B.That;for;to learn原因 Most of the Chinese learn English as a foreign l----- l后面填什么? I want a foreign friend to learn English,also,Ican help you learn Chinese,thanks What is a good way to l------ a foreign language? 1.It's hard but helpful to learn a foreign根据句意写出单词的正确形式.1.It's hard but helpful to learn a foreign 英语同意句句型转换To learn a foreign well is useful,we find.We find _______ ________ to learn a foreign language well. learn a foreign language 等于study a foreign language吗 To learn a foreign language we have to know the rules of ______. What is the best way to learn a foreign language?Which foreign language would you prefer to learn?再加一句：English or another one 的意思 i think ______(that/it) important for a student to learn a foreign language well.