The old man often looked back on the past days ________ he worked hard to make a living.
We all like our English teacher, ________ we have learned a lot.
He doesn’t ________ anything we may say to help him study math.
English now is also spoken as _______ foreign or second language in _______ South Asia.
I will help you ________ I don’t sleep for a night.
He devoted his whole life ________ animals in danger.