'it was difficult' is a correct and usable part of a sentence in written English and can be used when describing a challenging experience. For example, "It was difficult to climb the mountain, but we eventually made it to the top.".
"But it was difficult.
Yes, it was difficult.
It was difficult for Andy.
"It was difficult," she said.
It was difficult to argue.
"It was difficult," Tsonga said.
"It was difficult," Gilbride said.
I love the desktop app, it’s always running on my Mac. Ludwig is the best English buddy, it answers my 100 queries per day and stays cool.
Cristina Valenza
Retail Lead Linguist @ Apple Inc.