over the past year一定用现在完成时吗?
以前讲现在完成时时,老师说有over the past year就用现在完成时
但是现在课本上有这样一句话：
He was charged with breaking into several computer systems over the last year.
为什么前面是“He was”而不是“He had been”或“He has been”?（句中所说的he已被谋杀）