a. 极简单的, 明白的, 容易解决的, 时晴时阴的
在线英汉词典

open-and-shut的短语、例句：

open-and-shut adj completely straightforward and obvious 显然的; 明显的
As far as I can see the whole matter is open-and-shut. 我看整件事是一清二楚.
He´s obviously guilty it´s an open-and-shut case. 他显然有罪--此案昭然若揭.