The manager promised to keep us of how our business was going on.
A. informed
B. informing
C. being informed
D. to be informed
网友回答
(答案→)A. informed
B. informing
C. being informed
D. to be informed
解析：句意：经理答应让我们了解我们的生意进行的情况。inform sb of sth告诉某人某事；其被动：sb be inform of这里是keep sb done,这里sb与do之间是被动关系，故选A。