HE ………… WHEN I ………. IN, AND HE OBVIOUSLY ………. FOR A LONG TIME,BECA...
43. He ………… when I ………. in, and he obviously ………. for a long time,
because he ……….. very tired.
a. worked / came / had been working / was
b. was working / came / had been working / was
c. was working / came / has been working / was
d. worked / came / had worked / was
--> b