如果有个心烦意乱、忧心忡忡的母亲，一个完全无用的角色，那就是我。

I became a distraught, worried mother, a useless role if ever there was one.

《柯林斯英汉双解大词典》

如果没有眼神的交流，言语交际甚至是完全无用的。

Without eye contact verbal communication is rendered completely futile.

youdao

接着他完全的训练他自己来认识喝酒是完全无用的，并且放下了。

Then he thoroughly trains himself to regard the drinking of alcohol as utterly useless, and gives it up.

youdao

Now as an aside, I'll admit this is a completely useless program, much like the first couple of ones we did because why would you write a program just to solve this?

说点题外话，我承认这是一个完全无用的程序，跟我们之前写的两个程序一样,我们为什么需要写个程序来解决这个数学运算呢？

哈佛公开课 - 计算机科学课程节选