1.invisible means that no one observes that a woman is doing so much of work.eg - cooking, washing chlothes, sweeping, wiping, etc.(the list is never ending)
2.physically demanding means that it needs a lot of efforts.eg - sweeping, changing gas cylinder, wiping, washing cholthes(if there is no washing machine)
3.time consuming means that it needs a lot of time.( no eg. it is obvious that if there are so many jobs then it will consume a lot of time).