He doesn't know ______ English because he has studies it for

He doesn't know ______ English because he has studies it for 英语在线句子改错He doesn't know much English because he studies it f He doesn't know_English because he has studied（已经学习）it for o He doesn't have to ______ (make)learn ,because he studies ha He doesn't want to go there because he has been there for co he doesn't know ______about it he doesn't know He doesn't know how he_____improve his English. A.must B.has He doesn't know what to say,for it is the first time that he ______ can it be _____ he studies English? she doesn't know if he is _____or dead because harry is very upset because he doesn"t know( )