I heard that there would be a mixture of different accents in listening comprehension of CET4 ,not only American and British,however some accents are hard to be understood. Today,I had my first college English lesson,and I found my English teacher had a British accent.Though I can distinguish it,I still feel that British accent is strange;If heard other accents such as Australian,the situation may be worser.I only get accoustomed to American English,what should I do to improve my ability of understanding other accents?