It was 1920 ______ regular radio broadcasts began.
—Someone wants you on the phone. —________ nobody knows I am here.
We had to be patient because it ________ some time ________ we got the full results.
He was so deep in thought,thinking of the problem ________ he knocked into the tree without noticing it.
________ all of them are strong candidates,only one will be chosen for the post. (2011·陕西,19)
Please call my secretary to arrange a meeting this afternoon,or________it is convenient to you. (2011·江西,29)