一曝十寒的英文：
[Literal Meaning]
one/expose to the sun/ten/freeze
to sun something for one day and then freeze it for ten days

[解释]
曝：晒。原义指即使是最容易生长的植物，晒一天，冻十天，也不可能生长。比喻学习或工作一时勤奋，一时又懒惰，没有恒心。

[Explanation]
to work by fits and starts

[例子]
学习外语最怕一曝十寒，那样的话肯定学不好。

[Example]
For learning a foreign language, one should not work by fits and starts. If so, nobody can learn it well.

[英文等价词]
to work by fits and starts

spasmodic bouts of exercise are not very beneficial
一曝十寒的运动不会有多大好处。