We tried to sail in the boats we _____ (make) the previous day.
We tried to sail in the boats we 'd made the previous day.
I was covered in grass because I 've been cutting / 'd been cutting the lawn.
I was covered in grass because I'd been cutting the lawn.
It turned out that the exam was harder than we'd expected. --> The exam...
The exam turned out to be harder than we'd expected.