plain and simple 显而易见；简单明了

【例句】
If you expect to be trusted, start being more honest. It's as plain and simple as that!
如果你想要被人信任，那么请你把自己变得更加诚实，道理就是这么简单明了！

It was a rip-off, plain and simple.
这是一个不折不扣的冒牌货。