Question

【題目】（題文）（2017 上海市黃浦區(qū)九年級4月學業(yè)模擬考試）Listen! Someone __________ at the door. Please go and answer it.

A. knocks B. is knocking C. has knocked D. was knocking

Answer 1

【答案】B

【解析】句意：聽！有人在敲門。請去看一看。像Listen，look，now等表示現(xiàn)在時間，要用現(xiàn)在進行時態(tài)，現(xiàn)在進行時的構(gòu)成：be+doing；根據(jù)Listen!可知現(xiàn)在的時間，要用現(xiàn)在進行時態(tài)，結(jié)合句意和語境可知選B。