Between 4.5 and 3.8 billion years ago, the earth became so ______ that it was not clear whether the shape would last or not.
Though ________ money, his parents managed to send him to school. A. lacked B lacking of C. lack of D. lacking
He always brings me a pretty gift ____ he comes to visit me. A by the time B sometimes C every time D at times
. The report about the ______ surprised all the ______.
. Reading this instructive book, ___________ .
Five books on the shelf are found ______.