一般过去时,现在时和过去时的几组差异

Her brother was a chemist.(已去世)

Her brother is a chemist.(尚健在)

 

That's all I had to say.(话已说完)

That's all I have to say.(言之未尽)

 

It was so nice to see you.(离别时用)

It is so nice to see you.(见面时用)