adult|adults

我哥哥现在是个成年人了。

My brother is an ___adult now.

独自开车必须是成年人。

You must be an ___adult to drive a car alone.

实验需要一只成年雄性大鼠。

The experiment required an ___adult male rat.

成年人需支付入场费，儿童免费。

___Adults pay an admission charge but children get in free.

在博物馆，成年人需要买票。

At the museum, ___adults need to buy a ticket.