Дополнить предложения следующими словами: can, can't, mustn't, have to, don't have to, had to, didn't have to 1. when i was younger i could do gymnastics very well, but now i 2. my sister sing really well. she sings in a group. 3. you wear special clothes to climb a mountain. 4. you clean the car — i've done it. 5. i forget my mum's birthday this year — last year i forgot! 6. we walk up the stairs yesterday because peter is afraid of lifts. 7. the school bus didn't arrive this morning but i walk to school — my dad took me.