He is clever and hard-working, so he has reason to succeed in the exam.
You cannot accept an opinion ______ to you unless it is based on facts.
The sunlight is white and blinding, ________ hardedged shadows on the ground.
________ with care, one tin will last for six weeks.
Every day ________ a proverb aloud several times until you have it memorized.
All flights ________ owing to the heavy fog, many passengers could do nothing but take trains.