It is (was) ...that (which)1. It was in this country that a large scale production of motor-cars and trucks was first organized.
2. It is countries with relatively high wage rates which make the most use of labour-saving machinery.
3. It is the act of spending which influences the prices.
4 It is for this reason that the balance of payments figures are subject to revision in the months following their original publication.
5. It is because the fixed exchange rate puts the official reserves at risk that most governments favour some more flexible system.
6. It is the act of spending which influences the prices.
Which or That?
What is the difference between which (or who) and that,and how can you tell which one to use?
The basic question is whether you, or the person you are talking to, already know what it is that you are talking about. In the sentence 'I've lost the book that I was reading yesterday', that introduces information that the listener needs in order to know what book is being talked about. You can also say 'I've lost the book which I was reading yesterday'.
In 'This book, which I bought yesterday, is very interesting', which tells the listener something new about a book that has already been identified. You shouldn't use that in sentences of this kind.