As one of natural fires, its mechanism is very complex and difficult to control.

雷击火作为天燃火源是一种难以控制的自然现象，其形成机理极为复杂。

youdao

The quenching and tempering for large steel plate is a intractable problem as the large quenching distortion and difficult to control.

大型钢板调质是热处理行业中多年来难以控制变形、淬火变形大、十分棘手的难题之一。

youdao

The retaining screw is a weak part of the whole superstructure . The causes of the screw loosening and fracture are complex and difficult to control.

固位螺钉是整个种植义齿上部结构中比较薄弱的部分，其松动、折断的成因复杂且难以控制。

youdao

But he was also extremely large and difficult to control.

VOA: special.2009.02.23

The question is not so much how we control what happens to us but what do we do when we were faced difficult circumstances, and how we can make spiritual meaning even when difficult things happen to us.

问题不是我们能够掌控多少,而是当我们面对困境,能做些什么，我们怎样体现灵性的意义,即便我们面临困境。

普林斯顿公开课 - 人性课程节选

However,this is more difficult because it is harder to control the diets of people and because they live longer than other animals.

VOA: special.2009.09.01

Unlike power plants, which are few in number and so easier to regulate, cars are ubiquitous and much more difficult to control.

ECONOMIST: The future of energy

They may have certain inclinations which are powerful, and which may be difficult to control.

NPR: Gay Mormons Grapple with Faith, Sexuality

The costs of providing and managing care, as everyone also knows, can be very difficult to control, and the task of allocating the resources necessary to an effective infrastructure of care is one that the current cartel-like system is not doing very well.

FORBES: Obama, Religious Liberty, And The Constitution