Sentence examples for been difficult to maintain from inspiring English sources

It was a difficult project to get started and has been difficult to maintain.

That route is also hobbled by its use of diesel engines, which the railroad says have been difficult to maintain.

It has been difficult to maintain a grip on momentum, but Murray has generally been holding with much more ease.

Halsey said that since the Civil War it had been difficult to maintain the style of service to which cultivated Southerners were accustumed.

U.S. casualty rates have jumped rapidly since President Obama increased troops numbers – a move that initially spiked public support – but gains have been difficult to maintain.

As many people have abandoned landlines, the Newspoll landline-only surveys have been difficult to maintain, especially with younger voters who only have a mobile.

It's difficult to maintain continuity".

Such compromises, however, are difficult to maintain.

Others were difficult to maintain or were not used.

(Was this because the initial energy was difficult to maintain?

But such investment will be difficult to maintain.