Some people won't realize the importance of their health u________ they lose it.
The story isn't hard to understand, b________ there are no new words in it.
T________ Edison failed many times, he didn't give up and succeeded in the end.
The factory is usually noisy, ________ it is pretty quiet today.
Help others, ________ you'll feel happier.
(2018保定竞秀区二模) Last night I stayed up too late, ________ I'm really sleepy now.
