he is complaining ____ the hard work ____ his boss A\;to B about;to Cto;abot D about;with

he is complaining ____ the hard work ____ his boss A\;to B about;to Cto;abot D about;with

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正确答案是：B
 
【解析】：
He is complaining 【about 】 the hard work 【to】 his boss
他正在向他的老板抱怨工作辛苦.
complain about sth 抱怨某事
complain to sb 向某人抱怨