past simple/past continuous question

Hi all,

Can you please clarify this contrast for me:


'When I saw my grandmother, she was laughing'.

E.g. Surely the longer event here is visiting a person, the shorter laughing.

This is just one extract of one of my grammar books:

'We use past continuous tense to express LONG actions and we use simple past tense to express a SHORT action'.

This appears the complete opposite to the example I raised and was asked about by a student!:-?

Thanks in advance


Mak

I understand this sentence this way:

When I looked at my grandmother she was in the process of laughing.

This way I glanced at her shortly and she started laughing before I did it and continued after that

I agree with Anna- the idea is that when you first caught sight of her she was alughing, meaning that her laughter had begun before your arrival.

OK thank you both of you. However, could you please explain the issues involved with the tenses in regard this example then!'Hello Harry, how was your grandmother?''Oh, she was fine, appeared to be very happy and was laughing a lot!'Many thanksMAK