He began to __________ because every means _______ tried already.
Right now, lots of people search for products on the Internet but still buy them at stores. Internet shopping will really ____ when people are sure that it is safe.
This book is said to be a special one, as it ____ many events not found in other history books.
The students will discuss a number of cases ____ beginners of English fail to use the language properly.
— Sorry to have interrupted you. Please go on. — Where was I? — You ____ you didn’t like your present job.
We consider ____ absolutely necessary that we should open our door to the outside world.