Заполнить пропуски подходящей формой глагола to be. Сделать предложения вопросительными и отрицательными:
1. My mother … an economist, and my father … a food technologist. My friend’s parents … technologists, too. 2. Where … you from? – I … from Belarus. – And where … your friends from? – They … from Russia. 3. … your friend at the University at the moment? – No, he … not at the University, he … at home. 4.What … the weather like today? – It … cloudy, the sky … grey. I think it will rain today. 5. Our students … fond of chemistry. 

например - my mother is , my father is , my friends are

а как сделать предложения вопросительными и отрицательными?

если I - amесли you , they , we - areесли he she it - ismy mother is , my father is , my friends are , where are you