The contribution of geothermal energy to the world's energy future is difficult to estimate.

地热能对世界未来能源的贡献是难以估计的。

youdao

It's difficult to estimate the number of youngsters involved in home schooling where children are not sent to school and receive their formal education from one or both parents.

很难估计有多少年轻人接受家庭教育，在家庭教育中孩子没有被送去学校，而是从父母一方或双方那里接受他们的正式教育。

youdao

but the true value of the services is difficult to estimate.;

但是服务的真正价值是 很难估计的.

youdao

Because the tunnel economy is clandestine, it's difficult to estimate just how much money is being made.

VOA: standard.2010.06.17

It's very difficult to estimate portions.

估计"摄入量"是很困难的

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选

More difficult to estimate is the cost to Mindanao in lost opportunity and continuing poverty.

CNN: A Warrior Comes in From the Cold

He said it was difficult to estimate the true effect because cancer may develop only years after exposure to air pollution.

BBC: Traffic

But it is very difficult to estimate size of a species from a distance - especially if you are unfamiliar with them.

BBC: 'Big cat' Canadian lynx was on the loose in UK in 1903