It’s nearly 7 o’clock. Helen _______ come, but let’s wait for her for another 5 to 7 minutes.

---Do you know where David is? I couldn’t find him anywhere. ---Well. He ______ have gone far----his coat’s still here.

I insisted _____ to see a doctor, but he insisted nothing ____ wrong with him.

Some aspects(方面) of a teacher’s job ______ be tiring, and teachers often ______ work at inconvenient hours.

The chemistry teacher demanded that the laboratory report _________ immediately after the experiment was done.