5.They ___ (help)us since five this morning until now.应该填什么,怎么分析的?
问题描述:
5.They ___ (help)us since five this morning until now.应该填什么,怎么分析的?
答
have been helping是现在完成进行时的用法.表示从过去开始一直进行着直至现在.