这位教授昨天已经到达北大了 用英语怎么说

这位教授昨天已经到达北大了.
The professor arrived at Beijing University yesterday.
这句话应该用一般过去时.
如果要用现在完成时,要这么说：
The professor has been in Beijing University since yesterday.
再问： 那请问The professor had arrived in Beijing University since yesterday.对不？
再答： 如果用had就变成过去完成时了，但是教授他是昨天到，今天还在，从过去延续到现在，要用现在完成时。