around round 
作介词用的around与round通常可以互换,只不过美语常用around,而英语常用round,
例如：You can see the post office round/around that corner. (绕过那个弯你就可以看到邮局.但是一定要区别它们的不同之处：round可以用作形容词、副词、介词、动词、名词；而around只能用作副词或介词.
例如：The post office is just round (around) the house (用作介词). He has round face (用作形容词). The river rounded the stones. (用作动词)