1.На (чем?) на коньках - подлежащее.
2. Н.ф:клетки. Постоянные признаки: качественное, нарицательное, неодушевленное. Непостоянные: мн. ч, П. падеж.
3. (Как?) на коньках - обстоятельство.
1 Our dog ran away while I was talking To Sarah.
2 We
were in the garden when it started to rain.
3 Jane got angry yesterday because we were late.
4 When I heard about the prize, I got excited.
5 The girls laughed when they saw the funny film.
He was in the theatre. She was in the zoo. They were in the cinema.