challenge的词根词源为chal

例句

1、

Schools must meet the challenge of new technology.

学校必须迎接新技术的挑战。

2、

The company faces major challenges over the course of the next few years.

这家公司今后几年将面临重大的挑战。

3、

It was a direct challenge to the president's authority.

这是对主席权威的直接质疑。