9

She bought 9 books for her English class.

用法提示：数字9修饰名词books，表示数量，作形容词用。

He has 9 coins in his pocket.

用法提示：数字9后接名词coins，表示数量，体现形容词用法。

We need 9 chairs for the party.

用法提示：数字9修饰名词chairs，表示数量，作形容词用。