1 定义:现在完成进行时表示动作从过去某一时间开始，一直延续到现在，可能还要继续下去。
2 现在完成进行时的构成:现在完成进行时是由“have/has+been+动词的现在分词”构成
3 现在完成进行时的基本句型
肯定式 I/We have been working.
疑问式 Have you been working？
简略回答 Yes，I/we have. No，I/we haven't.
肯定式 He/She/It has been working.
疑问式 Has he/she/it been working？
简略回答 Yes，he/she/it has. No，he/she/it hasn't.
