When I try to understand ____ that prevents so many Americans from being as happy as one might expect, it seems to me that there are two causes.

– I’ve read another book this week.
– Well, maybe ____ is not how much you read but what you read that counts.

It was in 1990 ______ the medicine was tested on human patients.

It was ______ 7:30 that he _________ home yesterday, so his parents were very worried.

How time flies! It’s in two months _____we’ll say goodbye to our high school Life.

---- Is it in that factory __________ “Red Flag” cars are produced? 
---- No, they are produced in our factory.

It is in the west of China _____  _____ is no doubt that it is going to rain tomorrow.

It was ________I went there ________I began to know something about the matter.

It was along the Mississippi River _____ Mark Twain spent much of his childhood.

It ______ we had stayed together for a couple of weeks _____ I found we had a lot in common.