We didn’t believe it ______ we saw it with our own eyes. After all, to see is to believe.

The old temple _______ roof was damaged in storm is now under repair.

In college, you will discover ______ learning is about, from teacher-taught to self-learner．

How long can I _____ the English workbook—For two weeks.

ropped in on you at about four, p.m., but you didn’t answer the door.—— Oh, that was probably _________ I was playing badminton in the stadium nearby.