Past Perfect или Past Perfect Continuous 

01.    We sold our old house after we [had bought/had been buying] a new one.

02.    The road was blocked because a tree [had fallen/had been falling] on it.

03.    The street was icy in the morning as it [had been freezing/had frozen] all night.

04.    I was full of energy because I [had had/had been having] big lunch. 

05.    [Had you ever slept/Had you ever been sleeping] in a tent before your camping trip in Italy?

06.    There was no spagetti left. How much spagetti [had you cooked/had you been cooking] ?

07.    [I'd called/I'd been calling] Jane five times before she picked up the phone. 

08.    We [had been repairing/had repaired] the car for an hour when John appeared.

09.    She [had been teaching/had taught] for 40 years by the time she retired.

10.    I didn't give up even if I [had failed/had been failing] so many times.