___ by the teacher, Tom gotinto the classroom from the back door quietly.

What you needmost is to_______ what you have learned to your work.

Tom,did you break the vase I bought yesterday—It was not my 　　　.The floor was so slippery that I fell down and knocked it off the table.

Nancy spent half an hour _______ playing the pianoevery day.

Timmy likes Chinese very much. He can’t stop ________ it every day.