9、他的設(shè)計(jì)肯定還沒完成。
    誤：He mustn't have completed his design.
    正：He can't have completed his design.
    對(duì)比較有把握的推測(cè)，肯定句中用must，而否定句中用can't，對(duì)過去的推測(cè)，在must和can't后接完成形式。