Income tax return for year of assessment 2017

I just submitted my income tax return. It was supposed to be easy, but I was confused for a while.

They pre-filled my income tax return with figures for last year. I did not know that this was what they had done. I wondered - where did the figures came from? I do not recall submitting the figures before.

Anyway, I entered the actual figures for this year. The rental income on my property had dropped, so the actual figures were smaller than last year.

This year, they explained clearly that I could take 15% of the rental income as expenses, instead of declaring the actual expenses. Last year, they did not tell me about it. So, it was an improvement this year.

I look for the part where I had to declare my wife's income. I could not find it. Perhaps they have discontinued the joint declaration. This was rather bad. There aer many families, like me, where the spouse is not working and does not have any income. They should have allowed the taxpayer to make this declaration. If they have discontinued the practice, they should have mentioned it specifically.

I now have to make a separate declaration for my wife. She said, "I am not working and have no income. Why should I submit an incoem tax return?".

My answer - IRAS said so. The government said so. What can we do?