阅读下面短文，按照句子结构的语法性和上下文连贯的要求，在空格处填入一个适当的词或使用括号中词语的正确形式填空。每空不多于3个单词。

    Mary has ____ cousins. They are Betty, Peter, Bill and Ann.

    Mary is ____ (old) of five. Betty is thirteen years old. She is two years younger ____Mary and one year older than Peter. Ann is the youngest and she is naughty(淘气的). When her mother asks her ____（wash） hands, he never washes them ____ (careful). She only puts her hands in the water ____ a few seconds(秒) and took them out again. Betty and Peter are good at ____(run). They also like playing basketball. Peter plays ____(good) than Betty. Bill and Mary study in ____ same school. They study in No.1 School. Both of them always get good ____ (grade).

下列各组元素符号均表示金属元素的一组是（　　）

关于是我国自然环境和人类活动差异叙述错误的是（   ）