Whenmybabysisterfellasleep,Mumcameoutand

問題詳情：

When my baby sister fell asleep, Mum came out and ______ the door behind her carefully.

       A. rang                  B. shut                 

       C. knocked            D. answered

【回答】

B

知識點：動詞和動詞短語

題型：選擇題