DRILL:
CONVERT past simple >>> present perfect/ present perfect continuous

YESTERDAY.  the order arrived in the mail,
IT HAS BEEN 24 HOURS since the order arrived in the mail.
THE MAIL HAS BEEN SITTING AT THE DOOR since yesterday.

LAST WEEK she quit her job at the company
IT HAS BEEN ONE WEEK since she quit her job.
Since last week, SHE HAS BEEN LOOKING for a new job. 

2 DAYS AGO he got sick. 
HE HAS BEEN SICK for two days.
IT HAS BEEN TWO DAYS since he got sick. 

5 MINUTES AGO. I received an email from HR.
IT HAS BEEN 5 MINUTES since I received an email from HR. 

THIS PAST WEEKEND we went to Navacerrada
IT HAS BEEN A COUPLE DAYS since we went to Navacerrada.
WE HAVE BEEN THINKING about Navacerrada since our trip this past weekend. 

LAST TUESDAY we met with old friends.
IT HAS BEEN ONE WEEK since we met with old friends.

JUST NOW the explosion occurred
IT HAS BEEN MERE SECONDS since the explosion occurred.