90

My grandfather is 90 years old and still very active.

用法提示：这里的90作为数字修饰years，表示年龄。

She scored 90 out of 100 on the math test.

用法提示：这里的90表示分数，是名词性用法。

The company has 90 employees working in three shifts.

用法提示：这里的90作为数字修饰employees，表示数量。