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.
(2018长春改编) Work hard and be patient, ________ your dream won't come true.
It’s hard for us to say goodbye we have so many happy days to remember.
A.so B.because C.although D.until
