Pieces of bamboo or wood ________ books between 2nd and 5th century AD.A. used to formed B. used to formC. were used to form D. used to beforming
Don’t be too ______ about things you’re not supposed to know.
People have always been curious ______ how living things on the earth exactly began.
The father as well as the three children ______ every Sunday afternoon in winter.
—Did Alan enjoy seeing his old friends yesterday? —Yes, he did. He ______ his old friends for a long time.
.The moment I got home, I found I _______ my jacket on the playground.