【关于which的用法我写了一句话：Specifically,intermsofChinesewhichisthemostdifficultlanguageintheworld,thereareplentyofinformalusagepatternsandslanginChinese,whichwecannotmakesureiftheyarecourtesyexpressions.】

　　关于which的用法

　　我写了一句话：Specifically,intermsofChinesewhichisthemostdifficultlanguageintheworld,thereareplentyofinformalusagepatternsandslanginChinese,whichwecannotmakesureiftheyarecourtesyexpressions.

　　请问这句话能这么写吗?有语法错误吗?两个which的用法正确吗?这么多逗号应该不影响写作的质量吧?多谢回复!