According to the agreement, nobody let out how they spent the three days in the cave.
A. must
B. may
C. will
D. shall
网友回答
A. must
B. may
C. will
D. shall
解析:考查情态动词:句意:根据协议,没有人可以泄漏他们在山洞里面怎么度过的。Shall可以用于第三,第二人称,表示“命令,警告,允诺,规定”,这里是协议里面规定的,用shall,must必须,may可以,will愿意,选D。