问题
选择题
On returning from work, _____.
A．John found a letter in the mailbox
B．a letter was found in the mailbox
C．a letter was in the mailbox
D．the mailbox had a letter in it
答案
答案：A
根据题中的意思：一从工作回来，可知这个动作的执行者应是人，从四个选项中看出，只有A的主语是人，所以选A，句意：一从工作回来，约翰发现在邮箱里有一封信。所以选A。