The radar sets have been running for a long time without any

来源：学生作业帮编辑：搜狗做题网作业帮分类：英语作业时间：2024/06/30 21:26:33

The radar sets have been running for a long time without any trouble.为什么是用running不是用run?
2、Do you remember being introduced to Dr. Henry during your last visit?具体翻译

have been doing表示从过去到现在一直在进行
还记得上次你来访期间,把你介绍给了亨利博士/医生吗?
再问：那这个动作完成了吗？？
再答： have been doing表示从过去到现在一直在进行，现在还在进行

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