农业是我国两千多年封建社会的立国之本,中国是传统的农业大国。下列哪些现象是原始农业兴起和发展的重要标志( )
①农作物的出现 ②家畜饲养 ③聚落 ④磨制工具 ⑤城市的出现
写出下列名词的复数形式。
①May I have some ____ (plum), please? Sure.
②There are seven ____ (boy) in the playground.
③The woman has two ____ (baby).
④How many ____ (peach)? There is only one.
⑤There are two ____ (library) in our school.