1．现在完成时的构成
【语境领悟】
*I have been to Beijing three times so far.
到目前为止我已经去过北京三次了。
*He has not had anything since then.
从那以后他什么也没吃。
*We'll go to the cinema if the rain has stopped this afternoon.
若是下午雨停了，我们就去看电影。
*Great progress has been made in technology in China.
中国已经在科技方面取得了很大进步。
【知识归纳】
现在完成时的构成：
基本形式：have/has＋动词的过去分词
否定形式：have/has＋not＋动词的过去分词
被动形式：have/has＋been＋动词的过去分词
