My shoes ____ under the desk.

He could see the tall chimneys(烟囱) of the factory ______.

Carl, why not go and help your sister water the flowers there? —Why__________? I’m busy myself. Jack is lying on the grass doing nothing.

How long have you been studying at this school?—I have been studying here_____. [ ]

Only then ________ that he had lost a good chance of achieving his dream.