It is very ______ to learn German well,but a lot ________to learn Russian,while Chinese is______language in the world(di
问题描述：
It is very ______ to learn German well,but a lot ________to learn Russian,while Chinese is______language in the world(difficult)
答
It is very difficult to learn German well,but a lot more difficult to learn Russian,while Chinese is the most difficult language in the world.