已知等腰三角形的一边长为6,一个内角为60°,则它的周长是( )
A:12
B:51
C:18
D:20
①式子5m表示的含义是____.
②用式子表示没有看的页数是____.
聚落的两种主要形式是( )
根据句意及首字母或汉语提示完成单词。①China is a l____ country with a long history.②What s____ shoes would you like?③We often have rice,meat,____ (马铃薯) for lunch every day.④What ____ (饮料) would you have?⑤We have many great ____ (特色菜) in the restaurant.