if only的用法_if only加什么

If only 表示虚拟语气，如

If only I were you!如果我是你.

If only (expressing a strong wish表示强烈的愿望)但愿，真希望，只要...就好了：

If only he wouldn't eat so noisily.但愿他吃东西不这样大声就好了。/If he would only learn to eat quietly!但愿他学会吃东西时小声点就好了！