1 pen ( pens )
2 class ( classes )
3 box ( boxes )
4 ruler ( rulers )
5 teacher ( teachers )
6 name ( names )
7 number ( numbers )
8 year ( years )
9 eraser ( erasers )
10 map ( maps )
11 apple ( apples )
12 toy ( toys )
13 desk ( desks )
14 book ( books )
15 cake ( cakes )
16 egg ( eggs )
17 bus ( buses )
18 blackboaed ( blackboards )
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