Lawrence Craven, a doctor from the USA, is the author of several published reports, one of _____ introduced the idea in 1953 _____ aspirin could reduce the risk of heart attacks.
____ hands and knees Helen Thayer got the tent up.
The woman looks so worried. She seems ____ something valuable.
For women life sometimes seems ____ it is for men.
____ his homework, the boy went out to play games with his friends.
Guilin is famous ____ its beautiful hills and rivers, while Kunming is famous ____ the Spring City.