QUES: where 5 is the number of messages to save If n is not specified all available messages sent to the current room will be taken into account

correct the punctuation.

CORRECTED: where '5' is the number of messages to save. If n is not specified, all available messages sent to the current room will be taken into account.

QUES: In fact even if you hardly ever leave your cat alone you may still want to add another cat or two to the household since the European Burmese loves to spend time with other cats

correct the punctuation.

CORRECTED: In fact, even if you hardly ever leave your cat alone, you may still want to add another cat or two to the household, since the European Burmese loves to spend time with other cats.

QUES: The fastest and easiest way to open your AD2 file is to doubleclick it

correct the punctuation.

CORRECTED:
The fastest and easiest way to open your AD2 file is to double-click it.