Образовать множественное число knife,day,toy,sleep

Knife - knives day - days toy - toys а sleep - это глагол.

When i (rang) up my friend, he (was sleeping).when grandfather (was watching) tv, he (fell) asleep.when my friend (came) to see me, i (was doing) my homework.when i (was going) to the stadium, i (met) kate and ann.when nick (rang) me up yesterday, i (was helping) mother.when the children (were walking) through the wood, they (saw) a fox.when i (came) home, my sister (was washing) the floor.when mike (was playing) in the yard, he (found) a ball.when i (was drawing) yesterday, i (broke) two pencils.when i (met) tom, he (was going) to the shop.when i (looked) out of the window, the children (were playing) hide-and-seek.i (went) to the theatre yesterday.at seven o'clock yesterday i (went) to the theatre.what you (did) at 5 o'clock yesterday? -i (was playing) the piano.when i (came) to school, the children (were standing) near the classroom.we (were playing) in the yard the whole evening yesterday.when i (was preparing) breakfast in the morning, i (cut) my finger.last year i (went) to the united states. did you go to great britain last year? - no, i (went) to france.what you (did) yesterday? — i (was translating) a very long article