30. How long do you think it will be _____ we can find a new water source?
Is some German friends visited last week ?
Winter is the time of the yearthe days are short and nights are long.
--- What ______ when I phoned you? --- I ______ my work, and I was about to go out.
It was the first time ________ I ________ face to face with a thunder storm.
We were having a meeting _________ suddenly someone knocked at the door.