The fact has worried many scientists ______ the earth is getting warmer and warmer these years.
He transplanted the little tree to the garden _____ it was the best time for it.
Mrs. Brown was much disappointed to see the washing machine she had had____ went wrong again.
We expected there no problem with the publication of the book by now, but it is still being printed.
--- Do you think we can get to the airport in time? --- Yes, so long as we held up in any traffic jam?