By the time he was twelve, Edison __________ to make a living by himself.
Officials believe that more than one person _____ for the big fire.
The purpose of technology is to make it easier, ______ it more difficult.
____ being too large, the color and the style of the dress suit me well.
Come and see me whenever _______.
Many people agree that_______ knowledge of English is a must in ______ international trade today.