现在完成进行时一、现在完成进行时的定义现在完成进行时表示某动作从过去某个时间开始，一直延续到现在，并且还有可能持续下去。如：Those cats have been screaming for hours.那些猫叫了半天了。We have been waiting for him for two hours.我们等他等了两个小时。The dollar has been climbing steadily all week.整个星期美元一直在稳步增值。二、现在完成进行时的结构现在完成进行时由“have / has been +现在分词”构成。如：Sales have been dropping off badly.销售量一直减少得很厉害。I have been waiting for an hour and a half.我一直等了一个半小时了。Well have been living here for two years by next Sunday.到下星期日，我们在这里就住了整两年了。三、现在完成进行时有哪些主要用
