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These postcards are ________.
A．they B．theirs C．their D．them
Let's give ________ the cards.
[ ]
Who taught ______ math last year?
A．they B．their C．them D．theirs
Most students ride ________ bikes to school．
they
their
theirs
them
Who buys a nice present?
A．they
B．them
C．their
D．theirs