a or an: chair
a chair
S or ES: box → __________
boxes
S or ES: toy → __________
toys
S or ES: student → _________
students
S or ES: ruler → __________
rulers
A or An: teacher ⇒ ______
a teacher
A or An: pencil case ⇒ ______
a pencil case
A or An: uniform ⇒ ______
a uniform
A or An: orange ⇒ ______
an orange