Old people must be____ politely
If H2 burn in O2, we can get _____.
I’d like some _______ and _______.
—Oh, Mary is not here these days. Is she ill?— Her mother told me that she was in hospital.
----What will we do if we want to develop our village ?---- A lot of roads ______. I think .
We____here two hours ago . So we___ _here for two hours .