He began to take English _______ only when he left school.

Passengers will likely face the usual struggle to get their tickets during festivals, __________ at railway stations, where long lines are expected. 

 People say that young Chinese students’ eyesight keeps dropping _________ because of both too much homework and poor learning conditions.

Attention, coffee lovers! We have for you, the best coffee machine ___ invented.

 That night I felt especially lazy and went to bed ____ earlier than usual.