—Must we come to school at six tomorrow? —I am afraid you __A mustn't B needn't C must D can't

问题描述:

—Must we come to school at six tomorrow? —I am afraid you __A mustn't B needn't C must D can't
答案是C,我想怎么为什么(各路高手速度很快,我的问题补充提问一下)。
想知道其他答案为什么不能选。谢谢啦

C must.
解析:猜测的肯定回答用must,否定回答用can't
翻译:Must we come to school at six tomorrow?(我们明早一定要6点到校吗?)
—I am afraid you must.(我想你肯定得这么做.)