All his attempts to unlock the door were , because he was using the wrong key.
Information obtained from libraries is sooner forgotten than ____.
My parents tried their best to laugh _______ my fears for the coming examination.
After ______ seemed hours of waiting in line, finally it was our turn to pass the gateway.
________ treating the homeless man as a shame to society, Mrs. Wang provided him with food and water.
--Huang, would you mind if I used your Pipa for the coming singing competition? ---________