To mast a language is not an easy thing.请问：其中掌握用to mast还是用to master,或是别的词?

To mast a language is not an easy thing.请问：其中掌握用to mast还是用to master,或是别的词? What I to learn a foreign language well?What ——i——to learn a foreign language well？ 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 mast a lauguage is not an easy an thing.这句话对吗?to mast是掌握的意思吗,为什么查不到? Will you see _______(tomorrow)ball game on TV?It mast be very exciting.Tom ______ the backpack last week.He ______ it for a week (buy)Tell me about ________(you)and I want to know more about you in order to make it clear,i mast go up to___second floor and ask him ___second time. I knew little about English when I fist came to America.So I went to a language school.全文 i think ______(that/it) important for a student to learn a foreign language well. I think that it's a useful to learn a foreign-language.I think ____ _____ a foreign language ____ _____ I want to go to Paris where I can learn ___ French language.A.a B.an C.the D./ I think that it is important to master a foreign language.（同义句）I think ___ ___ ____ ___ a foreign language . 一道初四英语题同义句转换I think that is important to master a foreign language.=I think _____ _____ _____ _____ a foreign language. 英语改为简单句I think it is important to master a foreign language.I think____ ____ ____ ____ a foreign language. I don’t think possible to master a foreign language _______ memory work. 同义句转换：I think that it is important to master a foreign language i think it is easy to learn a foreign language.（改为同义句.） I think it’s very空(use) to learn a foreign language well i borrowed a book on how to improve body language from jack同义句