难度系数的英文：
degree of difficulty

参考例句：

But in springboard competitions, the degree of difficulty becomes higher.
而在跳板比赛时，难度系数就变得比较高了。

degree是什么意思：
n. 阶层；度；学位；程度

(degree of)importance,seriousness or influence
重要性、严重性或影响力（的程度）

current amplification degree
电流放大率

These universities are entitled to grant degrees.
这些大学有权授予学位。

A thermometer calibrated in degrees Fahrenheit.
用华氏温度校准的温度计。

The unemployment rate will rise by degrees.
失业率将会渐渐增加。

difficulty是什么意思：
n. 困难，艰难；难点，难事，困境；异议，反对，争论

I appreciate your difficulties.
我理解你的困难。

No difficulty can overwhelm us.
困难压不倒我们。

Inevitably, the proposal is running into difficulties.
提案意料之中地遭遇了麻烦。

The article spotlights the difficulties of the handicapped.
这篇文章突出报导了残疾人的困难。

These difficulties are intrinsic to such a situation.
这是这种情势下固然会有的困难。