7岁以前儿童的短时记忆容量也为7±2个信息单位。 ( )
参考答案：错
Throwing their hats into the air, the fans of the winning team _____ loud shouts of victory.
A．let down
B．let in
C．let go
D．let out
标示牌根据其用途可分为（）等。
A.警告类
B.允许类
C.提示类
D.禁止类
